Method for transmitting and receiving a group message in wireless communication system and device therefor

ABSTRACT

A method for transmitting and receiving a group messaging in a wireless communication system and an apparatus for the same is disclosed. Particularly, the method for receiving a group message performed by a user equipment (UE) in a wireless communication system include receiving assistance information indicating whether a paging message is transmitted for each UE group from a network node, receiving the paging message from the network node on a paging occasion of the UE, when the transmission of the paging message for a group to which the UE is belonged in indicated by the assistance information, and receiving the group message, when a group message transmission for the group to which the UE is belonged is activated by the paging message.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Application of InternationalApplication No. PCT/KR2015/006735, filed on Jun. 30, 2015, which claimsthe benefit of U.S. Provisional Application No. 62/019,845, filed onJul. 1, 2014, all of which are hereby incorporated by reference in theirentirety for all purposes as if fully set forth herein.

TECHNICAL FIELD

The present invention relates to wireless communication systems, andmore particularly, to a method for transmitting and receiving a groupmessaging in a wireless communication system that supports the MachineType Communication (MTC) and an apparatus for supporting the same.

BACKGROUND ART

Machine Type Communication (MTC) refers to a communication schemeincluding one or more machines and is also called Machine-to-Machine(M2M) communication. A machine in this context refers to an entity whichdoes not require direction intervention of a human. For example, notonly the device such as a meter equipped with a mobile communicationmodule or a vending machine, but also a user equipment such as a smartphone capable of connecting automatically to a network and performingcommunication without a human intervention is an example of the machine.Various examples of the machine are called MTC devices or terminals inthis document. In other words, MTC refers to the communication performedby one or more machines (namely, MTC devices) without incorporatinghuman operation/intervention.

MTC includes communication between MTC devices (for example,Device-to-Device (D2D) communication) and communication between an MTCdevice and an MTC Application Server. Examples of communication betweenan MTC device and an MTC application include communication between avending machine and a server; communication between a Point Of Sale(POS) device and a server; and communication between an electricity,gas, or water meter and a server. Besides, applications based on MTCinclude security, transportation, and health care.

DISCLOSURE Technical Problem

The group messaging means a way for transmitting the same message to aplurality of user equipments belonged to a group that is preconfigured.In the case of using the Commercial Mobile Alert System (CMAS) or theEarthquake and Tsunami Warning System (ETWS) indication as it is fortransmitting a group messaging, all of the user equipments belonged tothe same paging occasion read the group messaging at a time, andaccordingly, it raises a problem that unnecessary operation is performedand the power consumption occurs according to it.

In order to solve the problem, an object of the present invention is topropose a method for transmitting/receiving a group message to/by theuser equipments belonged to a group that requires the group messagingwithout a paging procedure of unintended user equipments and a cellbroadcast service being influenced by the group messaging in a wirelesscommunication system.

Technical Solution

According to an aspect of the present invention, a method for receivinga group message performed by a user equipment (UE) in a wirelesscommunication system may include receiving assistance informationindicating whether a paging message is transmitted for each UE groupfrom a network node, receiving the paging message from the network nodeon a paging occasion of the UE, when the transmission of the pagingmessage for a group to which the UE is belonged in indicated by theassistance information, and receiving the group message, when a groupmessage transmission for the group to which the UE is belonged isactivated by the paging message.

According to another aspect of the present invention, a UE for receivinga group message in a wireless communication system may include acommunication module for transmitting and receiving a signal with anexternal device and a processor for controlling the user equipment,where the processor is configured to perform receiving assistanceinformation indicating whether a paging message is transmitted for eachUE group from a network node, receiving the paging message from thenetwork node on a paging occasion of the UE, when the transmission ofthe paging message for a group to which the UE is belonged in indicatedby the assistance information, and receiving the group message, when agroup message transmission for the group to which the UE is belonged isactivated by the paging message.

According to still another aspect of the present invention, a method fortransmitting a group message performed by a network node in a wirelesscommunication system may include transmitting a group message indicationto a UE indicating whether a group message is transmitted and assistanceinformation for identifying for which UE group the group message is to aUE, and transmitting the group message to the UE, where whether the UEreceives the group message is determined based on the group messageindication and the assistance information.

According to still another aspect of the present invention, a networknode for transmitting a group message in a wireless communication systemmay include a communication module for transmitting and receiving asignal with an external device and a processor for controlling thenetwork node, where the processor is configured to perform transmittinga group message indication indicating whether a group message istransmitted and assistance information for identifying for which userequipment (UE) group the group message is to a UE and transmitting thegroup message to the UE, where whether the UE receives the group messageis determined based on the group message indication and the assistanceinformation.

Preferably, the assistance information may be transmitted through asystem information message or a common control channel.

Preferably, the assistance information may indicate a group identityallocated to each UE group or a modular value for an InternationalMobile Subscriber Identity (IMSI) for the UE.

Preferably, the assistance information may indicate a group messagediscriminating number which is predetermined for each UE group.

Preferably, the group message discriminating number may be configuredthrough an attach procedure or a tracking area update procedure.

Preferably, the group message may be transmitted through a systeminformation message.

Technical Effects

According to the embodiments of the present invention, a group messagemay transmit/receive efficiently a group message to/by the userequipments belonged to a group that requires the group messaging withouta paging procedure of unintended user equipments and a cell broadcastservice being influenced by the group messaging in a wirelesscommunication system.

The technical effects of the present invention are not limited to thetechnical effects described above, and other technical effects notmentioned herein may be understood to those skilled in the art from thedescription below.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included herein as a part of thedescription for help understanding the present invention, provideembodiments of the present invention, and describe the technicalfeatures of the present invention with the description below.

FIG. 1 illustrates an Evolved Packet System (EPS) to which the presentinvention can be applied.

FIG. 2 illustrates one example of an Evolved Universal Terrestrial RadioAccess Network (E-UTRAN) to which the present invention can be applied.

FIG. 3 illustrates a radio interface protocol structure between a UE andan E-UTRAN in a wireless communication system to which the presentinvention can be applied.

FIG. 4 illustrates an S1 interface protocol structure in a wirelesscommunication system to which the present invention can be applied.

FIG. 5 illustrates an EMM and ECM states in a wireless communicationsystem to which the present invention can be applied.

FIG. 6 illustrates a bearer structure in a wireless communication systemto which the present invention can be applied.

FIG. 7 illustrates transmission paths of a control plane and a userplane in an EMM registration state in a wireless communication system towhich the present invention can be applied.

FIG. 8 is a view exemplifying an ECM connection establishment procedurein a wireless communication system to which the present invention can beapplied.

FIG. 9 exemplifies a transmission of the system information in awireless communication system to which the present invention can beapplied.

FIG. 10 is a view exemplifying the modification of the systeminformation in a wireless communication system to which the presentinvention can be applied.

FIG. 11 is a view exemplifying a system information acquisitionprocedure in a wireless communication system to which the presentinvention can be applied.

FIG. 12 is a view exemplifying a paging procedure in a wirelesscommunication system to which the present invention can be applied.

FIG. 13 is a view for describing a paging occasion in a wirelesscommunication system to which the present invention can be applied.

FIG. 14 exemplifies architecture for the cell broadcast service in awireless communication system to which the present invention can beapplied.

FIG. 15 is a view exemplifying the serial number of the CBS message in awireless communication system to which the present invention can beapplied.

FIG. 16 is a view exemplifying the message code format of the CBSmessage in a wireless communication system to which the presentinvention can be applied.

FIG. 17 is a view exemplifying a warning message transmission procedurein a wireless communication system to which the present invention can beapplied.

FIG. 18 is a view exemplifying a warning message cancellation procedurein a wireless communication system to which the present invention can beapplied.

FIG. 19 is a view exemplifying Machine-Type Communication (MTC)architecture in a wireless communication system to which the presentinvention can be applied.

FIG. 20 is a view exemplifying a group messaging architecture based onCBS/PWS in a wireless communication system to which the presentinvention can be applied.

FIG. 21 is a view exemplifying a group messaging transmission procedurebased on the CBS/PWS architecture in a wireless communication system towhich the present invention can be applied.

FIG. 22 is a view exemplifying a group message transmission andreception method according to an embodiment of the present invention.

FIG. 23 is a view for describing a group paging occasion according to anembodiment of the present invention.

FIG. 24 is a view exemplifying a group message transmission andreception method according to an embodiment of the present invention.

FIG. 25 illustrates a block diagram of a communication device accordingto one embodiment of the present invention.

BEST MODE FOR INVENTION

In what follows, preferred embodiments according to the presentinvention will be described in detail with reference to appendeddrawings. The detailed descriptions provided below together withappended drawings are intended only to explain illustrative embodimentsof the present invention, which should not be regarded as the soleembodiments of the present invention. The detailed descriptions belowinclude specific information to provide complete understanding of thepresent invention. However, those skilled in the art will be able tocomprehend that the present invention can be embodied without thespecific information.

For some cases, to avoid obscuring the technical principles of thepresent invention, structures and devices well-known to the public canbe omitted or can be illustrated in the form of block diagrams utilizingfundamental functions of the structures and the devices.

A base station in this document is regarded as a terminal node of anetwork, which performs communication directly with a UE. In thisdocument, particular operations regarded to be performed by the basestation may be performed by a upper node of the base station dependingon situations. In other words, it is apparent that in a networkconsisting of a plurality of network nodes including a base station,various operations performed for communication with a UE can beperformed by the base station or by network nodes other than the basestation. The term Base Station (BS) can be replaced with a fixedstation, Node B, evolved-NodeB (eNB), Base Transceiver System (BTS), orAccess Point (AP). Also, a terminal can be fixed or mobile; and the termcan be replaced with User Equipment (UE), Mobile Station (MS), UserTerminal (UT), Mobile Subscriber Station (MSS), Subscriber Station (SS),Advanced Mobile Station (AMS), Wireless Terminal (WT), Machine-TypeCommunication (MTC) device, Machine-to-Machine (M2M) device, orDevice-to-Device (D2D) device.

In what follows, downlink (DL) refers to communication from a basestation to a terminal, while uplink (UL) refers to communication from aterminal to a base station. In downlink transmission, a transmitter canbe part of the base station, and a receiver can be part of the terminal.Similarly, in uplink transmission, a transmitter can be part of theterminal, and a receiver can be part of the base station.

Specific terms used in the following descriptions are introduced to helpunderstanding the present invention, and the specific terms can be usedin different ways as long as it does not leave the technical scope ofthe present invention.

The technology described below can be used for various types of wirelessaccess systems based on Code Division Multiple Access (CDMA), FrequencyDivision Multiple Access (FDMA), Time Division Multiple Access (TDMA),Orthogonal Frequency Division Multiple Access (OFDMA), Single CarrierFrequency Division Multiple Access (SC-FDMA), or Non-Orthogonal MultipleAccess (NOMA). CDMA can be implemented by such radio technology asUniversal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can beimplemented by such radio technology as Global System for Mobilecommunications (GSM), General Packet Radio Service (GPRS), or EnhancedData rates for GSM Evolution (EDGE). OFDMA can be implemented by suchradio technology as the IEEE 802.11 (Wi-Fi), the IEEE 802.16 (WiMAX),the IEEE 802-20, or Evolved UTRA (E-UTRA). UTRA is part of the UniversalMobile Telecommunications System (UMTS). The 3rd Generation PartnershipProject (3GPP) Long Term Evolution (LTE) is part of the Evolved UMTS(E-UMTS) which uses the E-UTRA, employing OFDMA for downlink and SC-FDMAfor uplink transmission. The LTE-A (Advanced) is an evolved version ofthe 3GPP LTE system.

Embodiments of the present invention can be supported by standarddocuments disclosed in at least one of wireless access systems includingthe IEEE 802, 3GPP, and 3GPP2 specifications. In other words, among theembodiments of the present invention, those steps or parts omitted forthe purpose of clearly describing technical principles of the presentinvention can be supported by the documents above. Also, all of theterms disclosed in this document can be explained with reference to thestandard documents.

To clarify the descriptions, this document is based on the 3GPPLTE/LTE-A, but the technical features of the present invention are notlimited to the current descriptions.

Terms used in this document are defined as follows.

-   -   Universal Mobile Telecommunication System (UMTS): the 3rd        generation mobile communication technology based on GSM,        developed by the 3GPP    -   Evolved Packet System (EPS): a network system comprising an        Evolved Packet Core (EPC), a packet switched core network based        on the Internet Protocol (IP) and an access network such as the        LTE and UTRAN. The EPS is a network evolved from the UMTS.    -   NodeB: the base station of the UMTS network. NodeB is installed        outside and provides coverage of a macro cell.    -   eNodeB: the base station of the EPS network. eNodeB is installed        outside and provides coverage of a macro cell.    -   User Equipment (UE): A UE can be called a terminal, Mobile        Equipment (ME), or Mobile Station (MS). A UE can be a portable        device such as a notebook computer, mobile phone, Personal        Digital Assistant (PDA), smart phone, or a multimedia device; or        a fixed device such as a Personal Computer (PC) or        vehicle-mounted device. The term UE may refer to an MTC terminal        in the description related to MTC.    -   IP Multimedia Subsystem (IMS): a sub-system providing multimedia        services based on the IP    -   International Mobile Subscriber Identity (IMSI): a globally        unique subscriber identifier assigned in a mobile communication        network    -   Machine Type Communication (MTC): communication performed by        machines without human intervention. It may be called        Machine-to-Machine (M2M) communication.    -   MTC terminal (MTC UE or MTC device): a terminal (for example, a        vending machine, meter, and so on) equipped with a communication        function operating through a mobile communication network and        performing an MTC function    -   MTC server: a server on a network managing MTC terminals. It can        be installed inside or outside a mobile communication network.        It can provide an interface through which an MTC user can access        the server. Also, an MTC server can provide MTC-related services        to other servers (in the form of Services Capability Server        (SCS)) or the MTC server itself can be an MTC Application        Server.    -   MTC application: services (to which MTC is applied) (for        example, remote metering, traffic movement tracking, weather        observation sensors, and so on)    -   MTC Application Server: a server on a network in which (MTC)        applications are performed    -   MTC feature: a function of a network to support MTC        applications. For example, MTC monitoring is a feature intended        to prepare for loss of a device in an MTC application such as        remote metering, and low mobility is a feature intended for an        MTC application with respect to an MTC terminal such as a        vending machine.    -   MTC subscriber: an entity having a connection relationship with        a network operator and providing services to one or more MTC        terminals.    -   MTC group: an MTC group shares at least one or more MTC features        and denotes a group of MTC terminals belonging to MTC        subscribers.    -   Services Capability Server (SCS): an entity being connected to        the 3GPP network and used for communicating with an MTC        InterWorking Function (MTC-IWF) on a Home PLMN (HPLMN) and an        MTC terminal.    -   External identifier: a globally unique identifier used by an        external entity (for example, an SCS or an Application Server)        of the 3GPP network to indicate (or identify) an MTC terminal        (or a subscriber to which the MTC terminal belongs). An external        identifier comprises a domain identifier and a local identifier        as described below.    -   Domain identifier: an identifier used for identifying a domain        in the control region of a mobile communication network service        provider. A service provider can use a separate domain        identifier for each service to provide an access to a different        service.    -   Local identifier: an identifier used for deriving or obtaining        an International Mobile Subscriber Identity (IMSI). A local        identifier should be unique within an application domain and is        managed by a mobile communication network service provider.    -   Radio Access Network (RAN): a unit including a Node B, a Radio        Network Controller (RNC) controlling the Node B, and an eNodeB        in the 3GPP network. The RAN is defined at the terminal level        and provides a connection to a core network.    -   Home Location Register (HLR)/Home Subscriber Server (HSS): a        database provisioning subscriber information within the 3GPP        network. An HSS can perform functions of configuration storage,        identity management, user state storage, and so on.    -   RAN Application Part (RANAP): an interface between the RAN and a        node in charge of controlling a core network (in other words, a        Mobility Management Entity (MME)/Serving GPRS (General Packet        Radio Service) Supporting Node (SGSN)/Mobile Switching Center        (MSC)).    -   Public Land Mobile Network (PLMN): a network formed to provide        mobile communication services to individuals. The PLMN can be        formed separately for each operator.    -   Non-Access Stratum (NAS): a functional layer for exchanging        signals and traffic messages between a terminal and a core        network at the UMTS and EPS protocol stack. The NAS is used        primarily for supporting mobility of a terminal and a session        management procedure for establishing and maintaining an IP        connection between the terminal and a PDN GW.

In what follows, the present invention will be described based on theterms defined above.

FIG. 1 illustrates an Evolved Packet System (EPS) to which the presentinvention can be applied.

The network structure of FIG. 1 is a simplified diagram restructuredfrom an Evolved Packet System (EPS) including Evolved Packet Core (EPC).

The EPC is a main component of the System Architecture Evolution (SAE)intended for improving performance of the 3GPP technologies. SAE is aresearch project for determining a network structure supporting mobilitybetween multiple heterogeneous networks. For example, SAE is intended toprovide an optimized packet-based system which supports various IP-basedwireless access technologies, provides much more improved datatransmission capability, and so on.

More specifically, the EPC is the core network of an IP-based mobilecommunication system for the 3GPP LTE system and capable of supportingpacket-based real-time and non-real time services. In the existingmobile communication systems (namely, in the 2nd or 3rd mobilecommunication system), functions of the core network have beenimplemented through two separate sub-domains: a Circuit-Switched (CS)sub-domain for voice and a Packet-Switched (PS) sub-domain for data.However, in the 3GPP LTE system, an evolution from the 3rd mobilecommunication system, the CS and PS sub-domains have been unified into asingle IP domain. In other words, in the 3GPP LTE system, connectionbetween UEs having IP capabilities can be established through anIP-based base station (for example, eNodeB), EPC, and application domain(for example, IMS). In other words, the EPC provides the architectureessential for implementing end-to-end IP services.

The EPC comprises various components, where FIG. 1 illustrates part ofthe EPC components, including a Serving Gateway (SGW), Packet DataNetwork Gateway (PDN GW), Mobility Management Entity (MME), Serving GPRSSupporting Node (SGSN), and enhanced Packet Data Gateway (ePDG).

The SGW operates as a boundary point between the Radio Access Network(RAN) and the core network and maintains a data path between the eNodeBand the PDN GW. Also, in case the UE moves across serving areas by theeNodeB, the SGW acts as an anchor point for local mobility. In otherwords, packets can be routed through the SGW to ensure mobility withinthe E-UTRAN (Evolved-UMTS (Universal Mobile Telecommunications System)Terrestrial Radio Access Network defined for the subsequent versions ofthe 3GPP release 8). Also, the SGW may act as an anchor point formobility between the E-UTRAN and other 3GPP networks (the RAN definedbefore the 3GPP release 8, for example, UTRAN or GERAN (GSM (GlobalSystem for Mobile Communication)/EDGE (Enhanced Data rates for GlobalEvolution) Radio Access Network).

The PDN GW corresponds to a termination point of a data interface to apacket data network. The PDN GW can support policy enforcement features,packet filtering, charging support, and so on. Also, the PDN GW can actas an anchor point for mobility management between the 3GPP network andnon-3GPP networks (for example, an unreliable network such as theInterworking Wireless Local Area Network (I-WLAN) or reliable networkssuch as the Code Division Multiple Access (CDMA) network and Wimax).

In the example of a network structure as shown in FIG. 1, the SGW andthe PDN GW are treated as separate gateways; however, the two gatewayscan be implemented according to single gateway configuration option.

The MME performs signaling for the UE's access to the network,supporting allocation, tracking, paging, roaming, handover of networkresources, and so on; and control functions. The MME controls controlplane functions related to subscribers and session management. The MMEmanages a plurality of eNodeBs and performs signaling of theconventional gateway's selection for handover to other 2G/3G networks.Also, the MME performs such functions as security procedures,terminal-to-network session handling, idle terminal location management,and so on.

The SGSN deals with all kinds of packet data including the packet datafor mobility management and authentication of the user with respect toother 3GPP networks (for example, the GPRS network).

The ePDG acts as a security node with respect to an unreliable, non-3GPPnetwork (for example, I-WLAN, WiFi hotspot, and so on).

As described with respect to FIG. 1, a UE with the IP capability canaccess the IP service network (for example, the IMS) that a serviceprovider (namely, an operator) provides, via various components withinthe EPC based not only on the 3GPP access but also on the non-3GPPaccess.

Also, FIG. 1 illustrates various reference points (for example, S1-U,S1-MME, and so on). The 3GPP system defines a reference point as aconceptual link which connects two functions defined in disparatefunctional entities of the E-UTAN and the EPC. Table 1 below summarizesreference points shown in FIG. 1. In addition to the examples of FIG. 1,various other reference points can be defined according to networkstructures.

TABLE 1 Reference point Description S1-MME Reference point for thecontrol plane protocol between E-UTRAN and MME S1-U Reference pointbetween E-UTRAN and Serving GW for the per bearer user plane tunnelingand inter eNodeB path switching during handover S3 It enables user andbearer information exchange for inter 3GPP access network mobility inidle and/or active state. This reference point can be used intra-PLMN orinter-PLMN (e.g. in the case of Inter-PLMN HO). S4 It provides relatedcontrol and mobility support between GPRS core and the 3GPP anchorfunction of Serving GW. In addition, if direct tunnel is notestablished, it provides the user plane tunneling. S5 It provides userplane tunneling and tunnel management between Serving GW and PDN GW. Itis used for Serving GW relocation due to UE mobility if the Serving GWneeds to connect to a non-collocated PDN GW for the required PDNconnectivity. S11 Reference point for the control plane protocol betweenMME and SGW SGi It is the reference point between the PDN GW and thepacket data network. Packet data network may be an operator externalpublic or private packet data network or an intra- operator packet datanetwork (e.g., for provision of IMS services). This reference pointcorresponds to Gi for 3GPP accesses.

Among the reference points shown in FIG. 1, S2a and S2b corresponds tonon-3GPP interfaces. S2a is a reference point which provides reliable,non-3GPP access, related control between PDN GWs, and mobility resourcesto the user plane. S2b is a reference point which provides relatedcontrol and mobility resources to the user plane between ePDG and PDNGW.

FIG. 2 illustrates one example of an Evolved Universal Terrestrial RadioAccess Network (E-UTRAN) to which the present invention can be applied.

The E-UTRAN system is an evolved system from the existing UTRAN system;for example, it includes the 3GPP LTE/LTE-A system. The E-UTRAN consistsof eNBs providing control plane and user plane protocol to the UE, andthe eNBs are connected to each other by means of X2 interface. The X2user plane interface (X2-U) is defined among the eNBs. The X2-Uinterface provides non-guaranteed delivery of the user plane Packet DataUnit (PDU). The X2 control plane interface (X2-CP) is defined betweentwo neighboring eNBs. The X2-CP performs the functions of contextdelivery between eNBs, control of user plane tunnel between a source eNBand a target eNB, delivery of handover-related messages, uplink loadmanagement, and so on. The eNB is connected to the UE through a radiointerface and is connected to the Evolved Packet Core (EPC) through theS1 interface. The S1 user plane interface (S1-U) is defined between theeNB and the Serving Gateway (S-GW). The S1 control plane interface(S1-MME) is defined between the eNB and the Mobility Management Entity(MME). The S1 interface performs the functions of EPS bearer servicemanagement, NAS signaling transport, network sharing, MME load balancingmanagement, and so on. The S1 interface supports many-to-many-relationbetween the eNB and the MME/S-GW.

FIG. 3 illustrates a radio interface protocol structure between a UE andan E-UTRAN in a wireless communication system to which the presentinvention can be applied.

FIG. 3(a) illustrates a radio protocol structure for the control plane,and FIG. 3(b) illustrates a radio protocol structure for the user plane.

With reference to FIG. 3, layers of the radio interface protocol betweenthe UE and the E-UTRAN can be divided into a first layer (L1), a secondlayer (L2), and a third layer (L3) based on the lower three layers ofthe Open System Interconnection (OSI) model, widely known in thetechnical field of communication systems. The radio interface protocolbetween the UE and the E-UTRAN consists of the physical layer, data linklayer, and network layer in the horizontal direction, while in thevertical direction, the radio interface protocol consists of the userplane, which is a protocol stack for delivery of data information, andthe control plane, which is a protocol stack for delivery of controlsignals.

The control plane acts as a path through which control messages used forthe UE and the network to manage calls are transmitted. The user planerefers to the path through which the data generated in the applicationlayer, for example, voice data, Internet packet data, and so on aretransmitted. In what follows, described will be each layer of thecontrol and the user plane of the radio protocol.

The physical layer (PHY), which is the first layer (L1), providesinformation transfer service to upper layers by using a physicalchannel. The physical layer is connected to the Medium Access Control(MAC) layer located at the upper level through a transport channelthrough which data are transmitted between the MAC layer and thephysical layer. Transport channels are classified according to how andwith which features data are transmitted through the radio interface.And data are transmitted through the physical channel between differentphysical layers and between the physical layer of a transmitter and thephysical layer of a receiver. The physical layer is modulated accordingto the Orthogonal Frequency Division Multiplexing (OFDM) scheme andemploys time and frequency as radio resources.

A few physical control channels are used in the physical layer. ThePhysical Downlink Control Channel (PDCCH) informs the UE of resourceallocation of the Paging Channel (PCH) and the Downlink Shared Channel(DL-SCH); and Hybrid Automatic Repeat reQuest (HARQ) information relatedto the Uplink Shared Channel (UL-SCH). Also, the PDCCH can carry a ULgrant used for informing the UE of resource allocation of uplinktransmission. The Physical Control Format Indicator Channel (PCFICH)informs the UE of the number of OFDM symbols used by PDCCHs and istransmitted at each subframe. The Physical HARQ Indicator Channel (PHICH) carries a HARQ ACK (ACKnowledge)/NACK (Non-ACKnowledge) signal inresponse to uplink transmission. The Physical Uplink Control Channel(PUCCH) carries uplink control information such as HARQ ACK/NACK withrespect to downlink transmission, scheduling request, Channel QualityIndicator (CQI), and so on. The Physical Uplink Shared Channel (PUSCH)carries the UL-SCH.

The MAC layer of the second layer (L2) provides a service to the RadioLink Control (RLC) layer, which is an upper layer thereof, through alogical channel. Also, the MAC layer provides a function of mappingbetween a logical channel and a transport channel; andmultiplexing/demultiplexing a MAC Service Data Unit (SDU) belonging tothe logical channel to the transport block, which is provided to aphysical channel on the transport channel.

The RLC layer of the second layer (L2) supports reliable datatransmission. The function of the RLC layer includes concatenation,segmentation, reassembly of the RLC SDU, and so on. To satisfy varyingQuality of Service (QoS) requested by a Radio Bearer (RB), the RLC layerprovides three operation modes: Transparent Mode (TM), UnacknowledgedMode (UM), and Acknowledge Mode (AM). The AM RLC provides errorcorrection through Automatic Repeat reQuest (ARQ). Meanwhile, in casethe MAC layer performs the RLC function, the RLC layer can beincorporated into the MAC layer as a functional block.

The Packet Data Convergence Protocol (PDCP) layer of the second layer(L2) performs the function of delivering, header compression, cipheringof user data in the user plane, and so on. Header compression refers tothe function of reducing the size of the Internet Protocol (IP) packetheader which is relatively large and contains unnecessary control toefficiently transmit IP packets such as the IPv4 (Internet Protocolversion 4) or IPv6 (Internet Protocol version 6) packets through a radiointerface with narrow bandwidth. The function of the PDCP layer in thecontrol plane includes delivering control plane data andciphering/integrity protection.

The Radio Resource Control (RRC) layer in the lowest part of the thirdlayer (L3) is defined only in the control plane. The RRC layer performsthe role of controlling radio resources between the UE and the network.To this purpose, the UE and the network exchange RRC messages throughthe RRC layer. The RRC layer controls a logical channel, transportchannel, and physical channel with respect to configuration,re-configuration, and release of radio bearers. A radio bearer refers toa logical path that the second layer (L2) provides for data transmissionbetween the UE and the network. Configuring a radio bearer indicatesthat characteristics of a radio protocol layer and channel are definedto provide specific services; and each individual parameter andoperating methods thereof are determined. Radio bearers can be dividedinto Signaling Radio Bearers (SRBs) and Data RBs (DRBs). An SRB is usedas a path for transmitting an RRC message in the control plane, while aDRB is used as a path for transmitting user data in the user plane.

The Non-Access Stratum (NAS) layer in the upper of the RRC layerperforms the function of session management, mobility management, and soon.

A cell constituting the base station is set to one of 1.25, 2.5, 5, 10,and 20 MHz bandwidth, providing downlink or uplink transmission servicesto a plurality of UEs. Different cells can be set to differentbandwidths.

Downlink transport channels transmitting data from a network to a UEinclude a Broadcast Channel (BCH) transmitting system information, PCHtransmitting paging messages, DL-SCH transmitting user traffic orcontrol messages, and so on. Traffic or a control message of a downlinkmulti-cast or broadcast service can be transmitted through the DL-SCH orthrough a separate downlink Multicast Channel (MCH). Meanwhile, uplinktransport channels transmitting data from a UE to a network include aRandom Access Channel (RACH) transmitting the initial control messageand a Uplink Shared Channel (UL-SCH) transmitting user traffic orcontrol messages.

The logical channel is on top of the transport channel and is mapped tothe transport channel. The logical channel can be divided into a controlchannel for delivery of control area information and a traffic channelfor delivery of user area information. Examples of the logical channelare a Broadcast Control Channel (BCCH), Paging Control Channel (PCCH),Common Control Channel (CCCH), Dedicated Control Channel (DCCH),Multicast Control Channel (MCCH), Dedicated Traffic Channel (DTCH), andMulticast Traffic Channel (MTCH).

FIG. 4 illustrates an S1 interface protocol structure in a wirelesscommunication system to which the present invention can be applied.

FIG. 4(a) illustrates the control plane protocol stack in the S1interface, and FIG. 4(b) illustrates the user plane interface protocolstructure in the S1 interface.

With reference to FIG. 4, the S1 control plane interface (S1-MME) isdefined between the eNB and the MME. Similar to the user plane, thetransport network layer is based on IP transmission. However, to ensurereliable transmission of message signaling, the transport network layeris added to the Stream Control Transmission Protocol (SCTP) layer whichsits on top of the IP layer. The application layer signaling protocol iscalled S1 Application Protocol (S1-AP).

The SCTP layer provides guaranteed delivery of application layermessages.

The transport IP layer employs point-to-point transmission for ProtocolData Unit (PDU) signaling transmission.

For each S1-MME interface instance, single SCTP association uses a pairof stream identifiers for the S-MME common procedure. Only part ofstream identifier pairs is used for the S1-MME dedicated procedure. TheMME communication context identifier is allocated by the MME for theS1-MME dedicated procedure, and the eNB communication context identifieris allocated by the eNB for the S1-MME dedicated procedure. The MMEcommunication context identifier and the eNB communication contextidentifier are used for identifying a UE-specific S1-MME signalingtransmission bearer. The communication context identifier is deliveredwithin each S1-AP message.

In case the S1 signaling transport layer notifies the S1AP layer ofdisconnection of signaling, the MME changes the state of the UE whichhas used the corresponding signaling connection to ECM-IDLE state. Andthe eNB releases RRC connection of the corresponding UE.

The S1 user plane interface (S1-U) is defined between eNB and S-GW. TheS1-U interface provides non-guaranteed delivery of the user plane PDUbetween the eNB and the S-GW. The transport network layer is based on IPtransmission, and the GPRS Tunneling Protocol User Plane (GTP-U) layeris used on top of the UDP/IP layer to deliver the user plane PDU betweenthe eNB and the S-GW.

EMM and ECM State

In what follows, EPS Mobility Management (EMM) and EPS ConnectionManagement (ECM) states will be described.

FIG. 5 illustrates an EMM and ECM states in a wireless communicationsystem to which the present invention can be applied.

With reference to FIG. 5, to manage mobility of the UE in the NAS layerdefined in the control planes of the UE and the MME, EMM-REGISTERED andEMM-DEREGISTERED states can be defined according to the UE is attachedto or detached from a network. The EMM-REGISTERED and theEMM-DEREGISTERED states can be applied to the UE and the MME.

Initially, the UE stays in the EMM-DEREGISTERED state as when the UE isfirst powered on and performs registering to a network through aninitial attach procedure to connect to the network. If the connectionprocedure is performed successfully, the UE and the MME makes transitionto the EMM-REGISTERED state. Also, in case the UE is powered off or theUE fails to establish a radio link (namely, a packet error rate for aradio link exceeds a reference value), the UE is detached from thenetwork and makes a transition to the EMM-DEREGISTERED state.

Similarly, to manage signaling connection between the UE and thenetwork, ECM-CONNECTED and ECM-IDLE states can be defined. TheECM-CONNECTED and ECM-IDLE states can also be applied to the UE and theMME. ECM connection consists of RRC connection formed between the UE andthe eNB; and S1 signaling connection formed between the eNB and the MME.In other words, establishing/releasing an ECM connection indicates thatboth of the RRC connection and S1 signaling connection have beenestablished/released.

The RRC state indicates whether the RRC layer of the UE is logicallyconnected to the RRC layer of the eNB. In other words, in case the RRClayer of the UE is connected to the RRC layer of the eNB, the UE staysin the RRC_CONNECTED state. If the RRC layer of the UE is not connectedto the RRC layer of the eNB, the UE stays in the RRC_IDLE state.

The network can identify the UE staying in the ECM-CONNECTED state atthe level of cell unit and can control the UE in an effective manner.

On the other hand, the network is unable to know the existence of the UEstaying in the ECM-IDLE state, and a Core Network (CN) manages the UE onthe basis of a tracking area unit which is an area unit larger than thecell. While the UE stays in the ECM-IDLE state, the UE performsDiscontinuous Reception (DRX) that the NAS has configured by using theID allocated uniquely in the tracking area. In other words, the UE canreceive a broadcast signal of system information and paging informationby monitoring a paging signal at a specific paging occasion for eachUE-specific paging DRX cycle.

When the UE is in the ECM-IDLE state, the network does not carry contextinformation of the UE. Therefore, the UE staying in the ECM-IDLE statecan perform a mobility-related procedure based on the UE such as cellselection or cell reselection without necessarily following an order ofthe network. In case the position of the UE differs from the positionrecognized by the network while the UE is in the ECM-IDLE state, the UEcan inform the network of the corresponding position of the UE through aTracking Area Update (TAU) procedure.

On the other hand, when the UE is in the ECM-CONNECTED state, mobilityof the UE is managed by an order of the network. While the UE stays inthe ECM-CONNECTED state, the network knows to which cell the UEcurrently belongs. Therefore, the network can transit and/or receiverdata to or from the UE, control mobility of the UE such as handover, andperform cell measurement with respect to neighboring cells.

As described above, the UE has to make a transition to the ECM-CONNECTEDstate in order to receive a general mobile communication service such asa voice or data communication service. As when the UE is first poweredon, the UE in its initial state stays in the ECM-IDLE state as in theEMM state, and if the UE successfully registers to the correspondingnetwork through an initial attach procedure, the UE and the MEE make atransition to the ECM connection state. Also, in case the UE has alreadyregistered to the network but radio resources are not allocated astraffic is not activated, the UE stays in the ECM-IDLE state, and if newuplink or downlink traffic is generated for the corresponding UE, the UEand the MME make a transition to the ECM-CONNECTED state through aService Request procedure.

FIG. 6 illustrates a bearer structure in a wireless communication systemto which the present invention can be applied.

When the UE is connected to a Packet Data Network (PDN) (which is thepeer entity of FIG. 6), PDN connection is established, which can becalled an EPS session. The PDN provides a service function such as theInternet or IP Multimedia Subsystem (IMS) through an external orinternal IP network of the service provider.

An EPS session comprises one or more EPS bearers. The EPS bearer refersto the transmission path of traffic generated between the UE and the PDNGW for the EPS to deliver user traffic. One or more EPS bearers can beset up for each UE.

Each EPS bearer can be classified into E-UTRAN Radio Access Bearer(E-RAB) or S5/S8 bearer, and the E-RAB can be further divided into aRadio Bearer (RB) and S1 bearer. In other words, one EPS bearercorresponds to one RB, one S1 bearer, and one S5/S8 bearer.

The E-RAB delivers packets of the EPS bearer between the UE and the EPC.If an E-RAB is generated, the E-RAB bearer is one-to-one mapped to theEPS bearer. A Data Radio Bearer (DRB) delivers packets of the EPS bearerbetween the UE and the eNB. If a DRB is generated, it is one-to-onemapped to the EPS bearer/E-RAB. The S1 bearer delivers packets of theEPS bearer between the eNB and the S-GW. The S5/S8 bearer delivers EPSbearer packets between the S-GW and the P-GW.

The UE binds the EPS bearer in the uplink direction with a Service DataFlow (SDF). An SDF is a group of IP flow(s) obtained by classifying (orfiltering) user traffic according to individual services. A plurality ofSDFs can be multiplexed to the same EPS bearer by including a pluralityof uplink packet filters. The UE stores mapping information between theuplink packet filter and the DRB to bind the SDF and the DRB with eachother for uplink transmission.

The P-GW binds the SDF with the EPS bearer in the downlink direction. Aplurality of SDFs can be multiplexed to the same EPS bearer by includinga plurality of downlink packet filters. The P-GW stores mappinginformation between the downlink packet filter and the S5/S8 bearer tobind the SDF and the S5/S8 bearer with each other for downlinktransmission.

The eNB stores one-to-one mapping information between the DRB and the S1bearer to bind the DRB and the S1 bearer with each other. The S-GWstores one-to-one mapping information between the S1 bearer and theS5/S8 bearer to bind the S1 bearer and the S5/S8 bearer with each otherfor uplink/downlink transmission.

The EPS bearer can be one of two types: a default bearer and a dedicatedbearer. The UE can have one default bearer and one or more dedicatedbearers for each PDN. The minimum basic bearer that the EPS session canhave with respect to one PDN is called default bearer.

The EPS bearer can be classified on the basis of its identity. The EPSbearer identity is allocated by the UE or the MME. The dedicatedbearer(s) is combined with the default bearer by a Linked EPS BearerIdentity (LBI).

If the UE establishes an initial connection to the network through aninitial attach procedure, an IP address is allocated to the UE togenerate a PDN connection, and a default bearer is generated in the EPSinterval. Unless the UE terminates the PDN connection, the defaultbearer is not released but maintained even when there is no trafficbetween the UE and the corresponding PDN; the default bearer is releasedwhen the corresponding PDN connection is terminated. At this time, notall the bearers acting as default bearers with respect to the UE acrossthe whole interval are not activated; the S5 bearer connected directlyto the PDN is maintained, and the E-RAB bearer related to radioresources (namely, DRB and S1 bearer) is released. And if new traffic isgenerated in the corresponding PDN, the E-RAB bearer is reconfigured todeliver traffic.

If the UE attempts to use a service of which the Quality of Service(QoS) (for example, Video on Demand (VoD) service) cannot be supportedby the default bearer while using a service (for example, the Internet)through the default bearer, a dedicated bearer is created when the UEdemands the high QoS service. In case there is no traffic from the UE,the dedicated bearer is released. The UE or the network can create aplurality of dedicated bearers depending on needs.

Depending on which service the UE uses, the IP flow can have differentQoS characteristics. When the EPS session for the UE is established ormodified, the network allocates network resources; or determines acontrol policy about QoS and applies the policy while the EPS session ismaintained. The aforementioned operation is called Policy and ChargingControl (PCC). A PCC rule is determined based on the operation policy(for example, a QoS policy, gate status, and charging method).

The PCC rule is determined in SDF unit. In other words, according to theservice that the UE uses, the IP flow can have different QoScharacteristics, IP flows having the same QoS are mapped to the sameSDF, and the SDF becomes the unit by which the PCC rule is applied.

Main entities which perform the PCC function include a Policy andCharging Rules Function (PCRF) and Policy and Charging EnforcementFunction (PCEF).

The PCRF determines a PCC rule for each SDF when the EPS session isestablished or modified and provides the PCC rule to the P-GW (or PCEF).After determining a PCC rule for the corresponding SDF, the P-GW detectsthe SDF for each IP packet transmitted or received and applies the PCCrule relevant to the corresponding SDF. When the SDF is transmitted tothe UE via the EPS, the SDF is mapped to the EPS bearer capable ofproviding appropriate QoS according to the QoS rule stored in the P-GW.

PCC rules can be classified by dynamic PCC rules and pre-defined PCCrules. A dynamic PCC rule is provided dynamically from the PCRF to theP-GW when the EPS session is established or modified. On the other hand,a pre-defined PCC rule is predefined in the P-GW andactivated/deactivated by the PCRF.

The EPS bearer includes a QoS Class Identifier (QCI) and Allocation andRetention Priority (ARP) as basic QoS parameters.

A QCI is a scalar used as a reference for accessing node-specificparameters which control bearer level packet forwarding treatment, wherethe scalar value is pre-configured by a network operator. For example,the scalar can be pre-configured by one of integer values ranging from 1to 9.

The main purpose of the ARP is to determine whether a request for anestablishment or modification of a bearer can be accepted or refusedwhen only limited amount of resources are available. Also, the ARP canbe used for the eNB to determine which bearer(s) to drop under thesituation of limited resources (for example, handover).

EPS bearers can be classified to Guaranteed Bit Rate (GBR)-type bearersand non-GBR type bearers depending on QCI resource type. A defaultbearer is always a non-GBR type bearer, but a dedicated bearer can be aGBR or non-GBR type bearer.

A GBR-type bearer has GBR and Maximum Bit Rate (MBR) as QoS parametersin addition to the QCI and the ARP. The MBR indicates that fixedresources are allocated (bandwidth is guaranteed) for each bearer. Onthe other hand, a non-GBR type bearer has an Aggregated MBR (AMBR) as aQoS parameter in addition to the QCI and the ARP. The AMBR indicatesthat instead of allocating resources to individual bearers, maximumbandwidth is allocated, where other non-GBR type bearers can be usedtogether.

As described above, if QoS of the EPS bearer is determined, QoS of eachbearer is determined for each interface. Since the bearer of eachinterface provides QoS of the EPS bearer according to the interface, theEPS bearer, RB, and S1 bearer all have a one-to-one relationship amongthem.

If the UE attempts to use a service of which the QoS cannot be supportedby the default bearer while using a service through the default bearer,a dedicated bearer is created.

FIG. 7 illustrates transmission paths of a control plane and a userplane in an EMM registration state in a wireless communication system towhich the present invention can be applied.

FIG. 7(a) illustrates ECM-CONNECTED state, and FIG. 7(b) illustratesECM-IDLE state.

If the UE successfully attaches to the network and enters theEMM-Registered state, the UE receives a service by using an EPS bearer.As described above, the EPS bearer is divided into the DRB, S1 bearer,and S5 bearer according to the respective intervals.

As shown in FIG. 7(a), in the ECM-CONNECTED state where user traffic ispresent, NAS signaling connection, namely, ECM connection (RRCconnection and S1 signaling connection) is established. Also, S11 GTP-C(GPRS Tunneling Protocol Control Plane) connection is establishedbetween the MME and the SGW, and S5 GTP-C connection is establishedbetween the SGW and the PDN GW.

Also, in the ECM-CONNECTED state, all of the DRB, S1 bearer, and S5bearer are set up (namely, radio or network resources are allocated).

As shown in FIG. 7(b), in the ECM-IDLE state where there is no usertraffic, the ECM connection (namely, RRC connection and S1 signalingconnection) is released. However, the S11 GTP-C connection between theMME and the SGW; and the S5 GTP-C connection between the SGW and the PDNGW are retained.

Also, in the ECM-IDLE state, the DRB and the S1 bearer are all released,but the S5 bearer is retained (namely, radio or network resources areallocated).

FIG. 8 is a view exemplifying an ECM connection establishment procedurein a wireless communication system to which the present invention can beapplied.

Referring to FIG. 10, a UE transmits a RRC connection request message toan eNB for requesting RRC connection (step, S801).

The RRC connection request message includes a UE Identity (e.g., SAEtemporary mobile subscriber identity (S-TMSI) or random ID) and anestablishment cause.

The establishment cause may be determined according to NAS procedure(e.g., attach, detach, tracking area update, service request andextended service request).

The eNB transmits a RRC connection setup message to the UE in responseto the RRC connection request message (step, S802).

After receiving the RRC connection setup message, the UE is shifted toRRC_CONNECTED mode.

The UE transmits a RRC connection setup complete message to the eNB forverifying successful completion of the RRC connection establishment(step, S803).

The UE transmits the RRC connection setup complete message with NASmessage (e.g., initial attach message, service request message, etc.)being included to the eNB.

The eNB acquires the service request message from the RRC connectionsetup complete message, and transmits this to the MME through theInitial UE message, which is S1AP message (step, S804).

The control signals between the eNB and the MME may be delivered throughS1AP message with S1-MME interface. The S1AP message is deliveredthrough S1 signaling connection for each user, and the S1 signalingconnection is defined by an identity pair (i.e., eNB UE S1AP ID and MMEUE S1AP ID) such that the eNB and the MME distinguish the UE.

The eNB allocates eNB UE S1AP ID and transmits the Initial UE messageincluding the eNB UE S1AP ID to MME, and the MME receives the Initial UEmessage and setup S1 signaling connection between the eNB and the MME byallocating MME S1AP UE ID.

System Information

A UE synchronizes with a cell through the cell discovery procedure, andacquires the physical layer ID of the cell and cell radio frame timing.And, when the UE complete such a procedure successfully, the UE shouldacquire the cell system information. Generally, the system informationmeans the information that the UE should know in order to access a celland to properly operate in a network or a specific cell.

The detailed features in relation to the system information may beincorporated by reference to the document 3GPP TS 36.331.

In the LTE/LTE-A system, the basic parameters (e.g., the systeminformation) required for the operation of the UE in the RRC_IDLE modeand the RRC_CONNECTED mode are broadcasted by dividing the parametersinto several information blocks.

The system information may be divided into a Master Information Block(MIB) and a plurality of System Information Blocks (SIBs). Hereinafter,the SIB type x (System InformationBlockTypex) is simply referred to as‘SIB x’.

Table 2 briefly illustrates the contents included in the systeminformation.

TABLE 2 System Information Content Master Information Downlink channelbandwidth, PHICH Block configuration, SFN System Information PLMN ID,tracking area code, cell selection Block 1 parameters, frequency band,cell barring, other SIB scheduling information System Information Accessclass barring, RACH, BCCH, Block 2 PCCH, PRACH, PDSCH, PUSCH, PUCCHparameter, UE timers and constants, uplink carrier frequency SystemInformation cell reselection parameters Block 3 System InformationIntra-frequency neighboring cell information Block 4 for cellreselection System Information Inter-frequency neighboring cellinformation Block 5 for cell reselection System Information UMTSneighboring cell information for cell Block 6 reselection SystemInformation GERAN neighboring cell information for cell Block 7reselection System Information CDMA2000 neighboring cell information forBlock 8 cell reselection System Information Home eNB name Block 9 SystemInformation ETWS(Earthquake and Tsunami Warning Block 10 System) primarynotification System Information ETWS(Earthquake and Tsunami WarningBlock 11 System) secondary notification System InformationCMAS(Commercial Mobile Alert System) Block 12 warning notificationSystem Information MBMS(Multimedia Broadcast Multicast Block 13Service)-related information System Information EAB(Extended AccessBarring) for access Block 14 control System Information informationrelated to mobility procedures Block 15 for MBMS reception SystemInformation information related to GPS(Global Block 16 PositioningSystem) time and UTC(Coordinated Universal Time)

Referring to Table 2, the MIB includes the parameter that is the mostessential, limited and required for obtaining other information from acell and the most frequently transmitted.

The MIB includes the information for a DL cell bandwidth. In the MIB, 4bits are used for indicating the DL bandwidth, and may indicatedifferent bandwidths up to 16.

In addition, the MIB includes the information of the PHICH configurationof a cell. A UE should know the PHICH configuration in order to receivethe L1/L2 control signaling on the PDCCH which is required for receivinga DL-SCH (i.e., the PDSCH). In the MIB, 3 bits indicate the informationof the PHICH configuration; herein, 1 bit represents whether the PHICHduration occupies one OFDM symbol or three OFDM symbols, and theremaining 2 bits notify the amount of reserved resource for the PHICH inthe control region.

In addition, the MIB includes the system frame number (SFN) of the radioframe on which the corresponding MIB is transmitted.

SIB 1 includes the information in relation to a cell access (a PLMN ID,a tracking area code, a cell selection parameter and a frequency band),and particularly, includes the scheduling information of other SIBsexcept SIB 1.

In addition, each of the system information is provided to a UE by beingdistinguished into information blocks.

The SIB numbers, the contents included in each SIB, and the like thatare illustrated in Table 2 are just an example, but the presentinvention is not limited thereto.

FIG. 9 exemplifies a transmission of the system information in awireless communication system to which the present invention can beapplied.

Referring to FIG. 9, the MIB uses the fixed schedule that has the periodof 40 ms, and is repeated within the period of 40 ms. The firsttransmission of the MIB is scheduled in subframe #0 of the radio frameof which System Frame Number (SFN) mod 4=0, and repeated in subframe #0of all of other radio frames within the period of 40 ms.

SIB 1 uses a fixed schedule that has a 80 ms period and is repeatedwithin the 80 ms period. The first transmission of SIB 1 is scheduled insubframe #5 of the radio frame of which SFN mod 8=0, and repeated insubframe #5 of all of other radio frames of which SFN mod 2=0 within the80 ms period.

A network may provide SIB 1 that includes the same parameter valuethrough the dedicated signaling (e.g., RRC Connection Reconfigurationmessage) as well as broadcasts the SIB.

The SIBs except SIB 1 is delivered in the system information (SI)message.

The mapping in the SI message of the SIB may be configured by thescheduling information list (schedulingInfoList) included in SIB 1. Thescheduling information list (schedulingInfoList) includes the schedulinginformation (schedulingInfo) of each SI message, and the schedulinginformation (schedulingInfo) includes the transmission period(si-Periodicity) of the SI message and the SIB mapping information(sib-MappingInfor).

In this case, each SIB is included only in a single SI message and oncein the corresponding SI message. The SIBs including the same schedulingrequirement (e.g., transmission period) may be mapped to the same SImessage. SIB 2 (SystemInformationBlockType2) is always mapped to the SImessage that corresponds to the first message in the list of the SImessages in the scheduling information list. The multiple SI messagesare transmitted in the same period.

The SI message is transmitted in the window in a time domain(hereinafter, referred to as ‘SI window’) using a dynamic scheduling.SIB 1 configures a SI window length (si-WindowLength).

Each SI message is in relation to a single SI window, and the SI windowsof different SI messages are not overlapped. That is, only one SImessage is transmitted in a single SI window.

The length of the SI window is the same for all SI messages. In the SIwindow, the corresponding SI message may be transmitted several times inthe radio frame of MBSFN subframe, UL subframe in TDD and the subframeexcept subframe #5 of radio frames of which SFN mod 2=0.

The system information is commonly applied to all UEs accessed in acell, and a UE should maintain the newest system information always forthe proper operation. In the case that the system information ischanged, a UE should know the time when an eNB transmits new systeminformation.

As described above, in order to notify that the system information ischanged or in order to trigger a UE so as to reacquire the systeminformation, a paging message may be used.

The change of the system information (except the ETWS, CMAS and EABparameters) occurs only in a specific radio frame. That is, amodification period is used. The system information is transmittedseveral times with the same contents within the modification period. Theboundary of the modification period is defined as the SFN value, SFNmod=0. Herein, m is a radio frame number that configures themodification period. The modification period is configured by the systeminformation.

FIG. 10 is a view illustrating the modification of the systeminformation in a wireless communication system to which the presentinvention can be applied.

When a network modifies (a part of) the system information, themodification is notified to the first UE. That is, the modification isperformed within a modification period. In the next modification period,the network transmits updated system information. The different shadesin FIG. 10 represent different types of system information. In the caseof receiving the modification notification, a UE acquires new systeminformation immediately after the next modification period is started.The UE applies the system information which is previously acquired untilacquiring new system information.

A paging message is used in order to notify the modification of thesystem information to the UE in the RRC_IDLE mode and the UE in theRRC_CONNECTED mode. When the UE receives a paging message that includesa system information modification (systemInfoModification) field, the UEknows that the system information is to be changed in a boundary of thenext modification period. However, even though the UE receives theinformation of the modification within the system information, anyfurther detailed information such as which system information is changedis not provided to the UE.

SIB 1 includes a system information value tag (systemInfoValueTag)indicating that a modification is occurred in the SI message. The UE mayuse the system information value tag in order to check whether the SImessage which is previously stored is still valid (e.g., the case ofreturning to coverage from exterior, etc.). In addition, the UE mayregard the system information as not valid in the case that three hourshave passed since the time when the UE successfully checks the systeminformation stored is valid.

When a part of the system information (e.g., the parameter (SIB 8 andSIB 16) which is regularly changed such as the ETWS information, theCMAS information and the time information, and the EAB parameter) ischanged, the network may not update the system information value tag.Similarly, when a part of the system information is changed, the networkmay not include a system information modification(systemInfoModification) field within a paging message.

In the case that the systemInfoValueTag in SIB 1 is checked after themodification period boundary is passed or a paging is not received, bytrying to find a system information modification(systemInfoModification) indication as much as at least amodificationPeriodCoeff number (e.g., 2, 4, 8 and 16) during themodification period in every modification period, the UE may check thestored system information to be valid.

In the case that the UE fails to receive the paging message during themodification period, the UE may assume that the system information willnot be changed in the next modification period boundary. When the UE inthe RRC_CONNECTED mode receives a paging message during the modificationperiod, the UE may determine whether the system information except theETWS information, the CMAS information and the EAB parameter is going tobe modified in the next modification period according to the presence ofthe system information modification (system InfoModification).

The UE in the RRC_CONNCTED mode which is available to support the ETWSand/or the CMAS tries to read the paging at least once in every defaultpaging cycle (defaultPagingCycle) in order to check whether the ETWSand/or CMAS notification is existed.

Hereinafter, the modification notification of the ETWS, CMAS and EABparameters will be described in more detail.

The ETWS primary notification and/or the ETWS secondary notification maybe occurred in any times. The paging message may be used in order tonotify whether the ETWS primary notification and/or the ETWS secondarynotification are existed to the UEs in the RRC_IDLE mode and theRRC_CONNCTED mode which are available to support the ETWS.

When the UE receives the paging message that includes an ETWSindication, the UE starts to receive the ETWS primary notificationand/or the ETWS secondary notification according to the schedulinginformation list (schedulingInfoList) included in SIB 1.

In the case that the UE receives the paging message that includes anETWS indication during acquiring the ETWS notification(s), the UEcontinues acquiring the ETWS notification(s) according to the schedulinginformation list (schedulingInfoList) which is previously acquired untilreacquiring the scheduling information list (schedulingInfoList) in SIB1.

The UE is not required to check periodically the scheduling informationlist (schedulingInfoList) included in SIB 1. However, when receiving thepaging message that includes the ETWS indication, the UE reacquires thescheduling information list (schedulingInfoList) included in SIB 1 inorder to check the scheduling modification for SIB 10 and SIB 11.

In the case that the ETWS is no more scheduled, the UE may receive thepaging message that includes the ETWS indication and/or the systeminformation modification (system InfoModification), or may not receiveit.

The ETWS primary notification is included in SIB 10, and the ETWSsecondary notification is included in SIB 11. The ETWS secondarynotification may be delivered with being segmented. The segmentationwhich is applied to a transmission of the ETWS secondary notification ina cell is fixed. That is, the ETWS secondary notification has the samesegmentation size that includes the same message identifier(messageIdentifier), serial number (serialNumber) and warning messagesegment number (warningMessageSegmentNumber). The ETWS secondarynotification corresponds to a single cell broadcasting (CB) data. Thiswill be described in detail below.

The CMAS notification may be occurred in any times. The paging messagemay be used in order to notify whether the one or more CMASnotifications are existed to the UEs in the RRC_IDLE mode and theRRC_CONNCTED mode which are available to support the CMAS.

When the UE receives the paging message that includes a CMAS indication,the UE starts to receive the CMAS notification according to thescheduling information list (schedulingInfoList) included in SIB 1.

In the case that the UE receives the paging message that includes anCMAS indication during acquiring the CMAS notification(s), the UEcontinues acquiring the CMAS notification(s) according to the schedulinginformation list (schedulingInfoList) which is previously acquired untilreacquiring the scheduling information list (schedulingInfoList) in SIB1.

The UE is not required to check periodically the scheduling informationlist (schedulingInfoList) included in SIB 1. However, when receiving thepaging message that includes the CMAS indication, the UE reacquires thescheduling information list (schedulingInfoList) included in SIB 1 inorder to check the scheduling modification for SIB 12.

In the case that SIB 12 is no more scheduled, the UE may receive thepaging message that includes the ETWS indication and/or the systeminformation modification (system InfoModification), or may not receiveit.

The CMAS notification is included in SIB 12. The CMAS notification maybe delivered with being segmented. The segmentation which is applied tothe transmission of the CMAS notification in a cell is fixed. That is,the CMAS notification has the same segmentation size that includes thesame message identifier (messageIdentifier), serial number(serialNumber) and warning message segment number(warningMessageSegmentNumber). The network does not apply theinterleaving in the transmission of the CMAS notification. That is, allsegments of the CMAS notification is transmitted before the segment ofanother CMAS notification. The CMAS notification corresponds to a singlecell broadcasting (CB) data. This will be described in detail below.

The EAB parameter modification may be occurred in any times. The EABparameter is included in SIB 14. The paging message may be used in orderto notify that the modification of the EAB parameter or SIB 14 is nomore scheduled to the UE in the RRC_IDLE mode which is available tosupport the EAB.

When the UE receives the paging message that includes the EAB parametermodification (eab-ParamModification), the UE starts to receive SIB 14according to the scheduling information list (schedulingInfoList)included in SIB 1.

In the case that the UE receives the paging message that includes theEAB parameter modification (eab-ParamModification) during acquiring SIB14, the UE continues acquiring SIB 14 according to the schedulinginformation list (schedulingInfoList) which is previously acquired untilreacquiring the scheduling information list (schedulingInfoList)included in SIB 1.

FIG. 11 is a view illustrating a system information acquisitionprocedure in a wireless communication system to which the presentinvention can be applied.

A UE uses the system information acquisition procedure in order toacquire the access stratum (AS) and non-access stratum (NAS) systeminformation which is broadcasted by a network. The system informationacquisition procedure is applied to both of the UE in the RRC_IDLE modeand the UE in the RRC_CONNECTED mode.

The UE starts the system information acquisition procedure whencompleting a cell selection (e.g., when turning on the UE), a cellreselection and handover, when entering another Radio Access Technology(RAT), when entering in the coverage from exterior, when receiving anotification indicating that the system information is modified, whenreceiving an indication that an ETWS notification is existed, whenreceiving an indication that a CMAS notification is existed, whenreceiving an indication that an EAB parameter is modified and when amaximum validity duration is elapsed.

Referring to FIG. 10, the UE receives the MIB from the network (step,S1101).

The MIB is mapped to the BCCH and transmitted in the BCH/PBCH. Asdescribed above, the MIB is scheduled in subframe #0 of the radio frameof which SFN mod 4=0, and which is repeated in subframe #0 of all otherradio frames in the corresponding period. And, the PBCH occupies 72subcarriers on the center of first four OFDM symbols in the second slotof subframe #0 of a radio frame.

The UE receives SIB 1 from the network using the parameter received fromthe MIB (step, S1102). And, the UE receives the system information ofthe network based on the scheduling information list(schedulingInfoList) acquired from SIB 1 (step, S1103).

SIB 1 is scheduled in subframe #5 of the radio frame of which SFN mod8=0, and which is repeated in subframe #5 of all other radio frames ofwhich SFN mod 2=2 within 80 ms period.

On the other hand, the remaining SIB except SIB 1 is transmitted bybeing mapped to the SI for each SIB that has the same transmissionperiod. As described above, the SI window length and the SI messagetransmission period are scheduled in SIB 1.

All SIBs are mapped to the BCCH and transmitted in the DL-SCH/PDSCH. ThePDCCH for the SIB delivers the DCI to which the CRC scrambled by thesystem information-RNTI (SI-RNTI) is attached, and identifies the PDSCHthat delivers the SIB from the PDCCH. The PDSCH resource allocationinformation for the SIB uses DCI formats 1A and 10. That is, DCI formats1A and 10 are scrambled by the SI-RNTI.

The UE may acquire the detailed time domain scheduling (and otherinformation, for example, frequency domain scheduling, a transmissionformat which is used, etc.) of the PDSCH that delivers the SI message bydecoding the SI-RNTI on the PDCCH. One SI-RNTI is used for addressingall SI messages not only SIB 1.

The UE may overwrite the system information acquired through the systeminformation acquisition procedure on the system information which isalready stored.

Paging

The paging procedure is used in order to transmit paging information toa UE in RRC_IDLE mode in network, or to notify change of systeminformation to a UE in RRC_IDLE/RRC_CONNECTED mode, or to notify ETWSprimary notification and/or ETWS secondary notification to all UEs inRRC_IDLE/RRC_CONNECTED mode, or to notify CMAS notification to a UE inRRC_IDLE/RRC_CONNECTED mode.

FIG. 12 is a view exemplifying a paging procedure in a wirelesscommunication system to which the present invention can be applied.

Referring to FIG. 12, an MME starts a paging procedure by transmitting apaging message to an eNB (step, S1201).

As described above, locations of UE in ECM-IDLE state is managed in theMME based on Tracking Area (TA). At the moment, since the UE may beregistered by one or more TAs, the MME may transmit a paging message toa plurality of eNBs that cover the cell belonged to the TA(s) where theUE is registered. Here, each cell may be belonged to only one TA, andeach eNB may include cells belonged to different TAs.

Herein, the MME transmits a paging message to each eNB through S1APinterface. Hereinafter, this may be referred to ‘S1AP paging message’.

Table 3 exemplifies the S1AP paging message.

TABLE 3 IE type IE/Group and Semantics Assigned Name Presence Rangereference description Criticality Criticality Message Type M 9.2.1.1 YESignore UE Identity M 9.2.3.10 YES ignore Index value UE Paging M9.2.3.13 YES ignore Identity Paging DRX O 9.2.1.16 YES ignore CN DomainM 9.2.3.22 YES ignore List of TAIs 1 YES ignore >TAI List Item 1 . . .EACH ignore <maxnoofTAIs> >>TAI M 9.2.3.16 — CSG Id List 0 . . . 1GLOBAL ignore >CSG Id 1 . . . 9.2.1.62 — <maxnoofCSGId> Paging PriorityO 9.2.1.78 YES ignore

Referring to Table 2, IE/Group Name represents a name of an informationelement (IE) or an IE group. ‘M’ in the Presence field is a mandatoryIE, and represents an IE/IE group included in a message always. ‘0’ isan optional IE and represents an IE/IE group included or may not beincluded in a message. ‘C’ is a conditional IE and represents an IE/IEgroup included in a message only when a specific condition is satisfied.The Range field represents a number of which repeated IEs/IE groups isavailable to be repeated.

The IE type and reference field represents a type of the correspondingIE (e.g., ENUMERATED, INTEGER, OCTET STRING, etc.), and in case that arange of a value that the corresponding IE may have is existed,represents the range of the value.

The Criticality field represents criticality information that is appliedto an IE/IE group. The criticality information means informationindicating how a reception terminal operates in case that the receptionterminal does not understand all or a part of the IE/IE group. The sign,‘-’, represents that the criticality information is not applied, and thesign ‘YES’ represents the criticality information is applied. ‘GLOBAL’represents that an IE and repeated IE have one piece of commoncriticality information. ‘EACH’ represents that each of repeated IE hasunique criticality information. Assigned Criticality field representsactual criticality information.

The information element (IE) or IE group included in the S1AP pagingmessage will be described in more detail below.

Message type IE distinguishes a message which is transmitted.

UE Identity Index value IE is used for an eNB to calculate Paging Frame(PF) (e.g., UE Identity Index=UE IMSI mod 1024).

UE paging identity IE is an identity for distinguishing a UE which ispaged, and is indicated by one of IMSI and SAE temporary mobilesubscriber identity (S-TMSI). The S-TMSI means an identity that isavailable to uniquely distinguish a UE among one MME group.

In case that a UE uses a UE-specific DRX cycle length, Paging DRX IE isused to calculate paging frame (PF) for an eNB. The UE may specify theDRX cycle length in the attach request message or tracking area update(TAU) message.

CN Domain IE indicates whether the paging is generated in circuitswitched (CS) domain or packet switched (PS) domain.

Tracking Area Identity (TAI) List IE is used to notify a TA in which apaging message should be broadcasted to an eNB. The TAI means anidentity which is used to uniquely distinguish TA.

Closed Subscriber Group (CSG) ID List IE represents a CSG set where a UEis prescribed. This prevents an eNB from paging to a UE in a CSG cellwhere the UE is not prescribed.

The eNB that receives S1AP paging message from the MME configures apaging message (hereinafter, referred to ‘RRC paging message’).

Table 4 exemplifies a RRC paging message.

TABLE 4 -- ASN1START Paging ::= SEQUENCE { pagingRecordListPagingRecordList OPTIONAL, -- Need ON systemInfoModification ENUMERATED{true} OPTIONAL, -- Need ON etws-Indication ENUMERATED {true} OPTIONAL,-- Need ON nonCriticalExtension Paging-v890-IEs OPTIONAL  -- Need OP }Paging-v890-IEs ::= SEQUENCE { lateNonCriticalExtension OCTET STRINGOPTIONAL, -- Need OP nonCriticalExtension Paging-v920-IEs OPTIONAL  --Need OP } Paging-v920-IEs ::= SEQUENCE { cmas-Indication-r9 ENUMERATED{true} OPTIONAL, -- Need ON nonCriticalExtension Paging-v1130-IEsOPTIONAL  -- Need OP } Paging-v1130-IEs ::= SEQUENCE {eab-ParamModification-r11 ENUMERATED {true} OPTIONAL, -- Need ONnonCriticalExtension SEQUENCE { } OPTIONAL  -- Need OP }PagingRecordList ::= SEQUENCE (SIZE (1..maxPageRec)) OF PagingRecordPagingRecord ::= SEQUENCE { ue-Identity PagingUE-Identity, en-DomainENUMERATED {ps, cs}, ... } PagingUE-Identity ::= CHOICE { s-TMSI S-TMSI,imsi IMSI, ... } IMSI ::= SEQUENCE (SIZE (6..21)) OF IMSI-DigitIMSI-Digit ::= INTEGER (0..9) -- ASN1STOP

Referring to Table 4, a single RRC paging message of UE may carryinformation of multiple S1AP paging messages. That is, the RRC pagingmessage may include multiple paging records (e.g., 16) for pagingmultiple UEs.

Each paging record includes a UE-Identity field and a CN domain field.This is a content which is transmitted from a S1AP paging message.

The system InfoModification field is not delivered from the S1AP pagingmessage, but is generated by an eNB. This field is used for triggeringsuch that a UE re-acquires a system information block (SIB) set.

The Extended Access Barring (EAB)-ParamModification field is used toindicate change of EAB parameter (SIB 14).

The ETWS-Indication field is not delivered from the S1AP paging message,but is generated by an eNB. This field is applied only to an ETWScapable UE, and is used to trigger such that the corresponding UEre-acquires SIB 1. The SIB 1 content indicates ETWS content in SIB 10and SIB 11 to a UE.

The CMAS-Indication field is applied only to a CMAS capable UE, and isused to trigger such that the corresponding UE re-acquires SIB 1. TheSIB 1 content indicates CMAS content in SIB 12 to a UE.

As such, the eNB that configures the RRC paging message transmitsdownlink control information (DCI) to which cyclic redundancy check(CRC) scrambled with paging-RNTI (P-RNTI) is attached to a UE on thePDCCH (step, S1202), and transmits the RRC paging message to the UE onthe PDSCH (step, S1203).

That is, an eNB delivers the RRC paging message through the PCCH logicalchannel, the PCH transport channel and the PDSCH physical channel to aUE.

In more detail, the eNB determines a PDCCH format according to the DCIthat will be sent to the UE, and attaches CRC to the DCI. According tothe owner or use of the PDCCH, a unique radio network temporaryidentifier (RNTI) is scrambled (or masked) to CRC. For the PDCCH for aspecific UE, a unique identity of UE (e.g., cell-RNTI; C-RNTI) may bemasked to CRC. Or, for the PDCCH for a paging message, a pagingindication identity (e.g., paging-RNTI; P-RNTI) may be masked to CRC.

That is, a UE monitors the PDCCH based on P-RNTI in a subframe belongedto its paging occasion 1212. And in order to detect the PDCCH masked byP-RNTI, the UE decodes the DCI transmitted on the PDCCH. The DCIindicates the PDSCH resource where the paging message is transmitted.And the UE decodes the RRC paging message from the PDSCH resourceindicated in the DCI.

The paging cycle 1213 may be determined in a cell-specific manner, ordetermined in a UE-specific manner. In addition, the paging occasion1212 is determined based on its paging cycle 1213 and its identity(i.e., IMSI) for each UE. Accordingly, the paging message is nottransmitted to all UEs on an available paging occasion 1211 from an eNB,but the paging message is transmitted on the paging occasion of thecorresponding UE. The paging occasion will be described in more detaillater.

The paging procedure may be used for notifying change of systeminformation, reception of cell broadcast message (i.e., ETWS/CAMSwarning message) and change of EAB as well as notifying reception ofindividual UE's Mobile Terminated (MT) call.

In case that a UE identity (e.g., IMSI or S-TMSI) is included (i.e., incase that the paging procedure is used for MT call) in one of pagingrecords included in the RRC paging message, the UE in RRC_IDLE modestarts a random access procedure for establishing RRC connection (e.g.,transmitting service request) with network.

Also, in case that system information modification(systemInfoModification) is included in the RRC paging message, a UEre-acquires the system information which is required by using a systeminformation acquisition procedure.

In addition, in case that the ETWS indication (etws-Indication) isincluded in the RRC paging message and a UE supports the ETWS, the UEre-acquires SIB 1 immediately. That is, the UE does not wait for theboundary of the next system information modification cycle. And if thescheduling information list (schedulingInfoList) included in SIB 1indicates that SIB 10 is existed, the UE acquires SIB 10 based on thescheduling information (schedulingInfor). In addition, if the schedulinginformation list (schedulingInfoList) included in SIB 1 indicates thatSIB 11 is existed, the UE acquires SIB 11 based on the schedulinginformation (schedulingInfor).

Also, CMAS indication (cmas-Indication) is included in the RRC pagingmessage and a UE supports CMAS, the UE re-acquires SIB 1 immediately.That is, the UE does not wait for the boundary of the next systeminformation modification cycle. And if the scheduling information list(schedulingInfoList) included in SIB 1 indicates that SIB 12 is existed,the UE acquires SIB 12 based on the scheduling information(schedulingInfor).

As such, in case that a cell broadcast message (i.e., ETWS/CAMS message)indication is included in the RRC paging message, a UE receives SIB 10,SIB 11 and SIB 12 by referring to schedulingInfoList of SIB 1. Thereceived SIB 10, SIB 11 and SIB 12 are delivered to a higher layer(e.g., RRC layer) of UE. In the higher layer of UE, the UE displays themessage identifier included in the cell broadcast message which isdelivered through SIB 10, SIB 11 and SIB 12 if the message identifier isincluded in a search list of the UE. And otherwise, the UE discard it.

In addition, in case that a UE in RRC_IDLE mode supports the EAB and theEAB parameter modification (eab-ParamModification) field is included inthe RRC paging message, the UE regards SIB 14 which is stored before isnot valid, and re-acquires SIB 1 immediately. That is, the UE does notwait for the boundary of the next system information modification cycle.And the UE re-acquires SIB 14 using the system information acquisitionprocedure.

Hereinafter, a paging occasion will be described.

FIG. 13 is a view for describing a paging occasion in a wirelesscommunication system to which the present invention can be applied.

3GPP LTE/LTE-A system defines discontinuous reception (DRX) technique ofUE in order to minimize the power consumption of UE.

A UE that uses the DRX monitors whether a paging message is transmittedonly one paging occasion for every Paging cycle (i.e., DRX cycle).

One Paging Frame (PF) means one radio frame that may include one or morepaging occasion(s).

One paging occasion (PO) means one subframe where the P-RNTI transmittedon the PDCCH that addresses a paging message may be existed. That is,the paging occasion is defined as a specific subframe in a PF that a UEchecks a paging message.

The PF and the PO are determined by using IMSI and DRX values of UE. TheUE may calculate the PF and the PO using its IMSI and DRX values. Inaddition, an eNB may also calculate the PF and the PO for each UEthrough the IMSI value which is delivered from the MME.

The DRX parameter (i.e., paging/PCCH configuration information) may betransmitted with being included in a common radio resource configuration(‘RadioResourceConfigCommon’) IE which is a RRC message used forspecifying common radio resource configurations. The common radioresource configuration IE may be transmitted through a RRC message suchas a RRC connection reconfiguration message or an SI message. The SImessage is a message which is used for transmitting one or more SIBs.

In addition, a UE may also request its DRX cycle through an attachrequest or a tracking area update (TAU) request message. At the moment,a DRX cycle length set that the UE may request is identical to thelength set which is used in the system information.

Table 5 exemplifies the PCCH configuration information in the commonradio resource configuration IE.

TABLE 5 PCCH-Config ::= SEQUENCE {  defaultPagingCycle ENUMERATED {rf32, rf64, rf128, rf256},  nB ENUMERATED { fourT, twoT, oneT, halfT,quarterT, oneEighthT,  } oneSixteenthT, oneThirtySecondT}

Referring to Table 5, the PCCH configuration information includes the‘defaultPagingCycle’ field that indicates a basic paging cycle lengthand the parameter ‘nB’ for acquiring the paging frame and the pagingoccasion.

The ‘defaultPagingCycle’ field has a basic paging cycle length, andsetup as one value of {rf32, rf64, rf128, rf256}. The rf means radioframe, and setup as one value of {rf32, rf64, rf128, rf256}. The rfmeans radio frame, and the numbers behind the ‘rf’ means the number ofradio frames. For example, if ‘defaultPagingCycle’=rf32, the pagingbasic cycle includes 32 radio frames, and if ‘defaultPagingCycle’=rf64,the paging basic cycle includes 64 radio frames.

The value of ‘nB’ parameter is indicated by a multiple of ‘T’ (4T, 2T,T, T/2, T/4, T/8, T/16 or T/32). For example, if ‘nB’=fourT, theparameter value of ‘nB’ is 4*T, and if ‘nB’=quarterT, the parametervalue of ‘nB’ is T/4.

Here, ‘T’ represents a DRX cycle of UE. ‘T’ is determined to thesmallest value among a UE-specific DRX cycle and the basic DRX cycle(‘defaultPagingCycle’ field value) which is broadcasted in the systeminformation. In case that the UE-specific DRX cycle is not setup by ahigher layer, ‘T’ is determined to the basic DRX cycle.

The PF is determined according to Equation 1 below.SFN mod T=(T div N)*(UE_ID mod N)  [Equation 1]

In Equation 1, N represents min (T, nB), and UE_ID represents (IMSI mod1024).

A UE does not monitor all subframes of the PF which is determined asabove, but monitors only the subframe which is distinguished by the POdetermined by Equation 2 below and Table 6 (or Table 7).i_s=floor(UE_ID/N)mod Ns  [Equation 2]

In Equation 2, Ns represents max(1, nB/T).

Table 6 exemplifies a subframe pattern for determining the PO in FDD.

TABLE 6 PO when PO when PO when PO when Ns i_s = 0 i_s = 1 i_s = 2 i_s =3 1 9 N/A N/A N/A 2 4 9 N/A N/A 4 0 4 5 9

Table 7 exemplifies a subframe pattern for determining the PO in TDD.

TABLE 7 PO when PO when PO when PO when Ns i_s = 0 i_s = 1 i_s = 2 i_s =3 1 0 N/A N/A N/A 2 0 5 N/A N/A 4 0 1 5 6

By applying i_s value which is determined by Equation 2 above to Table 6and Table 7, the subframe index that corresponds to the PO isdetermined. That is, a UE monitors only the subframe that corresponds tothe PO in the PF which is determined. In the example of FIG. 13, in thecase that the DRX cycle of the UE is 320 ms (i.e., 32 radioframes=rf32), radio frame 4 and radio frame 36, and so on may bedetermined to be the PF based on Equation 1 above. And, the UE monitorsthe paging message only in subframe 9 of radio frame 4 and subframe 9 ofradio frame 36 which is the PO determined based on Equation 2 and Table6 (or Table 7) above.

Cell Broadcast Service (CBS)

The CBS broadcasts the CBS message which is unacknowledged to allreceiving terminals in a specific area. The CBS is also called a CellBroadcast short message service. The CBS is standardized in the GSM inorder to provide a warning message, weather information, position-basednews, and so on to a UE on a national scale or in all city areas, andalso supported in the U MTS.

The CBS message is broadcasted to the geographic area which is known asthe cell broadcast area. This area may include one or more cells orentire PLMNs. Each of the CBS messages may be allocated to its owngeographic coverage area. The CBS message is generated from a pluralityof Cell Broadcast Entities (CBEs) in connection with a Cell Broad Centre(CBS). And, the CBS message is transmitted to a cell from the CBCaccording to the coverage requirement of the CBS.

The CBS message is periodically and repeatedly broadcasted by a cellduring a duration configured by an information provider. The period thatthe CBS message is repeatedly transmitted is according to theinformation that is included in the CBS message. For example, thedynamic information such as the load traffic information is required formore frequent transmission than the weather information. The repetitionduration is influenced whether the corresponding message considers thereception of the UE that moves in fast speed.

In order for the UE to selectively display the CBS message which isrequired by a user, the message class for classifying coding scheme ofCBS message and the type of information included in the CBS message isallocated.

A Public Warning System (PWS) is referred to as the general WarningNotification System which is provided by a mobile communication providerthat directly delivers the warning information provider and the warninginformation that provides a warning to the provider by sensing adisaster and warning situation to a UE.

The PWS warning message is delivered to a UE through the CBS mechanism.

The PWS provides a service so as to distribute the Earthquake andTsunami Warning System (ETWS), the Commercial Mobile Alert System(CMAS), the Korean Public Alert System (KPAS) and the European PublicWarning System (EU-Alert) warning message in the GSM, the UMTS and theE-UTRAN.

FIG. 14 exemplifies architecture for the cell broadcast service in awireless communication system to which the present invention can beapplied.

FIG. 14A illustrates the GSM network architecture, FIG. 14B illustratesthe UMTS network architecture, and FIG. 14C illustrates the EvolvedPacket System (EPS) network architecture.

The GSM network architecture according to FIG. 14A includes the cellbroadcast entity (CBE), the cell broadcast center (CBS), the BaseStation Controller (BSC) and the Base Transceiver Station (BTSs).

The CBS message is generated from the CBEs and delivered to the BSC viathe CBC. And, the BTSs included in the notification area broadcasts theCBS message under the control of the BSC, and a UE receives the CBSmessage.

In the UMTS network architecture, the GSM based station subsystem (BSS)according to FIG. 14B is replaced by the Universal Terrestrial RadioAccess Network (UTRAN) that includes the Radio Network Controller (RNC)and the Node B.

The CBC is configured as a part of the core network, and connected to arouting node (e.g., 3G SGSN via the Bc reference point). Accordingly,the CBC may be reached to all RNCs via the user plane of the Iuinterface.

The details in relation to the logical interface protocol between theCBC and the RNC may be incorporated by reference to the document 3GPP TS25.419, and the details in relation to other UTRAN related interface maybe incorporated by reference to the document 3GPP TR 25.925.

Based on the requirement for the architecture and the cell broadcastcore network, the core network element such as the Mobile SwitchingCenter (MSC), the Visitor Location Register (VLR), the Home LocationRegister (HLR), and so on are not included in order to deliver the CBSservice.

Referring to FIG. 14C, the CBS message is generated from the cellbroadcast entity (CBE), and the CBEs is connected to the correspondingcell broadcast center (CBC). The CBE divides the CBS message into aplurality of pages.

The CBC performs the scheduling function that manages the CBS message.The CBC is configured as a part of the core network and connected to theMME through the SBc reference point.

The details in relation to the interface protocol between the CBC andthe MME may be incorporated by reference the document 3GPP TS 29.168 andthe details in relation to the interface between the MME and the eNB maybe incorporated by reference to the document 3GPP TS 36.413.

The CBS message is broadcasted to the cells included in the notificationarea, and a UE receives the CBS message.

Hereinafter, the CBS message will be described. In order to describeclearly, the E-UTRAN is mainly described, but the technical feature ofthe present invention is not limited thereto.

That is, since the CBS transmission procedure is used in order todeliver the warning message in the E-UTRAN, it may be understood thatthe warning message below has the same meaning as the CBS message.

Message Parameter

Table 8 illustrates a high layer description of the warning messagecontents.

TABLE 8 Parameter Message Identifier Serial Number CB data (WarningMessage Content E-UTRAN) Data Coding Scheme

Referring to Table 8, the Message Identifier is the parameter fordistinguishing the source and type of the warning message.

The Serial Number is the parameter for distinguishing a specific warningmessage which is transmitted from the source and type indicated by themessage identifier.

The Data Coding Scheme is the parameter for distinguishing the languageand coding scheme applied to the warning message.

The CB data is the parameter that includes the contents of the warningmessage. The parameter is made up of the parameter included in the“Warning Message Content E-UTRAN” IE of the ‘WRITE-REPLACE WARNINGREQUEST’ message which is received from the CBC.

In the case of the ETWS, the description for the warning messagecontents is applied only to the secondary notification.

The details in relation to the warning message may be incorporated byreference to the document 3GPP TS 26.331.

Message Identifier

The Message Identifier is 16 bits and the parameter for identifying thesource and type of the CBS message. For example, ‘Automobile Association(=source)’ and ‘Traffic Report (=type)’ may correspond to one value. Aplurality of CBS messages may be generated from the same source and/orthe same type. These may be distinguished by serial numbers that will bedescribed below. The message identifier is coded in binary.

A UE receives and displays the CBS message that has a message identifierincluded in ‘search list’. The search list may include the Subscriberidentity module (SIM) and the message identifier included in the UE. Inthe case that there is a limit in the performance in relation to thenumber of message identifiers that the UE is available to search for,the message identifier stored in the SIM may have higher priority thanthe message identifier stored in the UE.

The UE may discard the CBS message of which message identifier valuerange is between A000 hex (hexadecimal-AFFF hex unless the UE receivesit from the Home Public Land Mobile Network (HPLMN), the EquivalentHPLMN (EHPLMN), the HPLMN or the PLMN which is equivalent to the EHPLMN.

A network may use the message identifier only in the range 4352-6399(1100 hex-18FF hex) for the PWS. When the message identifier of therange is existed in the search list, the UE tries to receive the CBSmessage.

Serial Number

A plurality of CBS messages may be generated from the same source and/orthe same type. These may be distinguished by serial numbers. That is,the serial number is the parameter for distinguishing the CBS message inthe same message identifier. This will be described by referring to thedrawing below.

FIG. 15 is a view exemplifying the serial number of the CBS message in awireless communication system to which the present invention can beapplied.

Referring to FIG. 15, the serial number is an integer of 16 bits, anddistinguishes a specific CBS message from the source and type indicatedby the message identifier. The CBS message may have the length from oneto fifteen pages. The serial number is changed whenever the CBS messagethat has the same message identifier is changed.

Two octets of the serial number includes a geographical scope (GS)indicator of 2 bits, a message code of 10 bits and an update number of 4bits.

The most significant bit (MSB) of the update number is bit 3 of octet 2.The MSB of the message code is bit 5 of octet 1, and the leastsignificant bit (LSB) is bit 4 of octet 2. The MSB of the GS is bit 7 ofoctet 1.

1) The message code may be summary information (subject/theme) or acommand of the CBS message.

The message code distinguishes the CBS message which is generated fromthe same source and type (i.e., the same message identifier). Themessage code is allocated by a PLMN operator.

The message code distinguishes different themes. For example, it isassumed that the value for the message identifier is ‘AutomobileAssociation (=source)’ and ‘Traffic Report (=type)’. Here, each of‘collision at A1 J5’, ‘a wild animal appears at A32 J4’ and ‘slowvehicle speed at M3 J3’ may correspond to a value for the message code.

In the case of the CBS message transmission for the ETWS (i.e., in thecase that the message identifier has the value for the ETWS), a part ofthe message code may activate an emergency user alert to a UE, and maycommand a message popup for notifying it to a user. The message codeformat will be described by reference to the drawing below.

FIG. 16 is a view exemplifying the message code format of the CBSmessage in a wireless communication system to which the presentinvention can be applied.

Referring to FIG. 16, the MSB (i.e., bit 5 of octet 1) of the messagecode may include emergency user alert fields and the next bit (i.e., bit4 of octet 1) may include popup fields.

The emergency user alert field includes other user alert means such asan alarm tone or vibration according to the performance of a UE.

The popup instruction has precedence over the configuration of GSrelated to the data coding scheme (DCS) message class and display mode.

Table 9 exemplifies coding of the emergency user alert field and thepopup field.

TABLE 9 Field Code Instruction to Terminal Emergency User 0 Noinstruction as to emergency user alert Alert 1 Activate emergency useralert Popup 0 No instruction as to popup 1 Activate popup on the display

2) The geographical scope (GS) defines an applicable area by thereceived message and a display mode.

The GS indicates the geographical area where a intrinsic message code isuniquely distinguished and the display mode. The CBS message may not bebroadcasted by all cells in the geographical area.

When two CBS messages that have the same serial number/messageidentifier are received by two different cells, the GS is used in orderto determine whether the CBS messages are actually identical.

Especially, the GS notifies the following information related to the CBSmessage to a UE.

-   -   Only cell wide: it means that the CBS message displayed is        disappeared from a screen when a UE selects the next cell and        the CBS message received from the next cell is regarded as a new        message.    -   PLMN wide: it means that the message code and/or update number        should be changed for the new CBS message in the next cell of        the corresponding PLMN. The CBS message is related to the PLMN        broadcasted, and accordingly the change of the PLMN (including        the change to another PLMN that is an ePLMN) means that the CBS        message is a new message.    -   Location Area wide (applied in the GSM): according to whether        the next cell belongs to the same location area of the present        cell, the CBS message that has the same message code and update        number is determined to be a new message in the next cell.    -   Service Area wide (applied in the UMTS): according to whether        the next cell belongs to the same service area of the present        cell, the CBS message that has the same message code and update        number is determined to be a new message in the next cell. Here,        the service area may be made up of one cell only.    -   Tracking Area wide (applied in the E-UTRAN): according to        whether the next cell belongs to the same tracking area of the        present cell, the alert message that has the same message code        and update number is determined to be a new message in the next        cell.

The display mode indicates whether the CBS message is always displayedas “immediate” or as “normal” only when a user wants to see it. Ineither case, the CBS message is displayed only in the case that themessage identifier in included in a search list in a UE.

Table 10 exemplifies coding of the GS field.

TABLE 10 GS Code Display Mode Geographical Scope 00 Immediate Cell wide01 Normal PLMN wide 10 Normal Location Area wide in GSM, Service Areawide in UMTS, Tracking Area wide in E-UTRAN 11 Normal Cell wide

Referring to table 10, ‘immediate’ indicates to be displayed directly asdefault, and ‘normal’ indicates to be displayed under a user interactionas default.

3) The update number indicates the contents changes of the same CBSmessage (that is, the CBS messages that have the same messageidentifier, the geographical scope, and the message code)

That is to say, the update number is a value that distinguishes an olderversion and newer version of the same CBS messages in the geographicalarea indicated. The message identifier and the serial number mayguarantee the uniqueness of the corresponding CBS message. A new CBSmessage has an update number ‘0000’, and the update number may beincreased by 1 every time the CBS message is updated.

Warning Message Delivery Procedure

The maximum size of the warning message in the E-UTRAN is different fromthe UTRAN/GERAN.

The eNB may receive the warning messages duplicated. The duplicatedmessages may be searched by checking the message identifier and theserial number field. The duplicated messages are not transmitted on awireless interface.

The warning message broadcasted is delivered to a plurality of eNBsthrough the MME. The broadcast and repetition of a new message for eachcell is scheduled by the eNB(s).

The general warning message transmission procedure is described byreferring the following drawing.

FIG. 17 is a view exemplifying a warning message transmission procedurein a wireless communication system to which the present invention can beapplied.

Referring to FIG. 17, the network registration and security (forexample, mutual authentication) procedure is performed (step, S1701).

The step 1701 (S1701) is performed whenever a UE connects to a network(e.g., power on).

The CBE delivers the emergency information to the CBC through theemergency broadcast request message by collecting the PWS emergencyinformation (step, S1702).

The CBE may be a government branch or a private institution. Theemergency information may include a warning type, a warning message, animpacted area, a warning duration/time period, and so on.

The CBC distinguishes the MMEs to which the CBS message is required tobe transmitted using the impacted area for warning, the warninginformation element is constructed.

Additionally, the CBC delivers the write-replace warning request messageincluding the warning message that is to be broadcasted, a messageidentifier, a serial number, a tracking area ID list, a warning arealist, an operation and maintenance centre (OMC) ID, a concurrent warningmessage (CWM) indicator, a response message transmission indication(Send Write-Replace-Warning-Indication), a global eNB ID, a repetitionperiod, an extended repetition period, number/No of broadcast requested,etc. to the MME (step, S1703).

The tracking area ID list is used only by the MME, and the MME uses itin order to select an eNB to which the write-replace warning requestmessage is delivered.

The warning area list indicates an area to which the warning message isrequired to be broadcasted. The warning area list is made up of the cellID list or the TAI list or the emergency area ID list. The warning arealist is used only by an eNB. The eNB is configured with the TAI to whichthe eNB itself provide a service or the cell ID and the emergency areaID to which the eNB itself belongs. The eNB checks whether to match thecontents of the warning area list to the ID which is configured to theeNB itself, and distinguishes cells for allocating the warning message.The warning area list IE is a selective information element.Accordingly, in the case that the warning area list IE does not exist,it may be understood that are all cells to which the eNB provides aservice. The number of cell ID may be limited according to the size ofmessage on SBc and S1-MME. The emergency area ID is unique in the PLMN.

The write-replace warning request message may include the OMC ID.

The OMC ID indicates the identifier of the OMC to which the trace recordis going to be transmitted. Therefore, in the case that the OMC IDexists in the write-replace warning request message, it indicates theOMC to which the trace record generated in step, S1711, is going to betransmitted.

In the case that the PLMN supports the broadcast of the coexisted (orconcurrent) warning message, the CBC configures the CWM indicator in allthe write-replace warning request messages. The CWM indicator indicatesthat the warning message received from eNB is a new message scheduledfor the concurrent broadcast while the broadcasting of another warningmessage is progressed.

The send write-replace-warning indication instructs the MME to transmitthe write-replace warning indication to the CBC. Therefore, in the casethat the CBC requests to deliver the broadcast scheduled area list tothe CBC itself through the write-replace warning indication message forthe warning message to the MME, the CBC configures sendwrite-replace-warning indication. The broadcast scheduled area listindicates that the broadcast is successfully started.

The repetition period indicates the period of the broadcasted warningmessage in seconds, and has a value between 0 and 4095.

The extended repetition period indicates the period of the broadcastedwarning message in seconds. In the case that the repetition period valueis greater than 4095, it has a value between 4096 and (217-1).

The number of broadcasts requested represents the number that the CBSmessage is broadcasted. The number of broadcasts requested may have thevalue up to 65535. If the value is set to be 0, the CBS message isindefinitely (i.e., till the kill-message request/indication istransmitted) broadcasted.

The MME transmits the write-replace warning confirm message in responseto the write-replace warning request message to the CBC (step, S1704).

The Write-Replace Warning Confirm message indicates that the MME startsto distribute the warning message to the eNB.

The Write-Replace Warning Confirm message may include unknown trackingarea list. The unknown tracking area list indicates a tracking area towhich a request unknown by the MME is not delivered.

In the case that the Write-Replace Warning Confirm message is notreceived by the CBC in an appropriate time interval, the CBC tries todeliver the warning message through another MME in the same pool area.

The attribute (parameter) shown previously is only one example, and apart of the attribute (parameter) illustrated may be included or abovethis, an additional attribute (parameter) may be more included.

Also, the attribute (parameter) that is included in the warning messageis transparently delivered from the CBC to the UE (that is, it isdelivered to eNB).

In the case that the CBC receives the write-replace confirm message fromthe MME, the CBC informs that the warning message begins to be deliveredby transmitting the emergency broadcast response message to the CBE(step, S1705).

The MME delivers the write-replace warning request message to the eNBswhich are included in the warning area (step, S1706).

The MME uses the tracking area ID list in order to determine an eNB inthe delivery area, in the case that the tracking area ID list is emptynor the global eNB ID is not received from the CBC, the MME delivers thewrite-replace warning request to all eNBs that are connected to the MMEitself. In the case that the global eNB ID is received by the CBC, theMME delivers the write-replace warning request to the eNB only indicatedby the global eNB ID.

The eNB broadcasts the warning message to cells according to theattribute of the received warning message (step, S1707), transmits thewrite-replace warning response message to the MME and confirms the factthat the warning message is broadcasted (step, S1708).

The eNB determines cells where the message is broadcasted by using thewarning area information. And, the eNB transmits the warning message tothe corresponding cell according to the repetition period (extendedrepetition period) and the number of broadcast requested value.

When the broadcasting of the warning message is already under progressand the CWM indicator is included in the write-replace warning requestmessage, the eNB does not interrupt the existing broadcast message butstarts to broadcast a new message at the same time. Otherwise, the eNBimmediately replace the existing broadcast message with a new message.

The eNB regularly broadcasts the warning message according to theattribute configured by the CBC to which the warning message isdistributed.

In the case that the UE is configured to receive the warning message,the UE informs the user of the received warning message (step, S1709).

In the case that the warning type is ‘earthquake’, ‘tsunami’, or‘earthquake and tsunami’, the UE immediately inform the user of it. Inthe case that the warning type is ‘test’, the UE discards the primarynotice without the user alarm.

In the case that there exists the send warning-message-indicationparameter in the write-replace warning request message that is receivedin the previous step, S1703, the MME transmits the broadcast scheduledarea list that includes the write-replace warning indication message toCBC (step, S1710).

The Broadcast Scheduled Area List may include the Broadcast CompletedArea List that the MME receives from eNB. The MME may combine thebroadcast completed area lists that the MME receive from eNB.

In step S1708, the MME determines whether the warning message deliveryis succeeded or failed from the write-replace warning response messagethat is received from eNB, and generates the trace record for it (step,S1711).

At this point, in order for the trace record to be delivered to thedesignated destination (i.e., OMC ID), the OMC ID received in step,S1703 is recorded on the trace record.

Warning Message Cancel Procedure

When the CBE requests to cease on-going broadcast of the warningmessage, the warning message cancel procedure is performed. It isdescribed referring to the below drawing.

FIG. 18 is a view exemplifying a warning message cancel procedure in awireless communication system to which the present invention can beapplied.

Referring to FIG. 18, the CBE starts the warning message cancelprocedure by transmitting the stop emergency broadcast request message(for example, a message identifier and a serial number) to the CBC(step, S1801).

The CBC transmits the stop warning request message (a messageidentifier), a serial number, a tracking area ID list, a warning area,an OMC ID, and a send stop warning indication to the MME(s) (step,S1802).

The Stop Warning Request message may include the OMC ID. In the casethat the OMC ID exists, it indicates the OMC to which the trace recordgenerated in step, S1808 is going to be transmitted.

In the case that the CBC requests the broadcast completed area list thatis broadcasted through the stop warning indication message for thewarning message to the MME, the Send Stop Warning Indication factor isconfigured.

The MME transmits the Stop Warning Confirm message in response to theStop Warning Request to the CBC (step, S1803).

The Stop Warning Confirm message indicates to the CBC that the MMEstarts to distribute the Kill Request message to the eNB.

In case that the CBC does not receive the Stop Warning Confirm messagein an appropriate time interval, the CBC tries to deliver the stopwarning request message through another MME in the same pool area.

In the case that the CBC receives the stop warning confirm message fromthe MME, the CBC informs that the warning message cancel procedure isstarted by transmitting the Stop Emergency Broadcast Response message tothe CBE (step, S1804).

The MME delivers the request received from the CBC to the eNB throughthe Kill Request message (step, S1805).

The MME uses the tracking area ID list in order to determine the eNB inwhich the broadcasting of the warning message is ongoing. In the casethat the tracking area ID list is empty, the kill request message isdelivered to all the eNBs that are connected to the MME.

The eNB stops broadcasting the warning message distinguished by a serialnumber and the message identifier in an area distinguished by thewarning area. And, the eNB confirms that broadcasting the warningmessage is ceased by transmitting the kill response message to the MME(step, S1806).

When the Warning Area is empty, it may be interpreted to be all cellsthat the eNB serves.

In the case that a Send Warning-Message-Indication parameter is existedin the Stop Warning Request message received in step, S1802 above, theMME delivers the Broadcast Cancelled Area List received from the eNBwith being included in the Stop Warning Indication message (step,S1807). The MME may combine the Broadcast Cancelled Area Lists receivedfrom the eNB.

When the CBC receives the Stop Warning Indication message transmissionfrom the MME, the CBC stops the Stop Warning Indication messagereception for the corresponding warning message, and then releases theserial number of the corresponding warning message.

From the Kill Response message received from the eNB in step, S1806generates a trace record (e.g., the number of broadcasted message in adesignated warning area, etc.) related to the cancelled message (step,S1808).

In this case, the OMC ID received in step, S1802 is recorded in thetrace record so that the trace record is delivered to a designateddestination (i.e., the OMC ID).

Machine-Type Communication

FIG. 19 is a view exemplifying Machine-Type Communication (MTC)architecture in a wireless communication system to which the presentinvention can be applied.

A UE used for the MTC (or an MTC UE) and an end-to-end applicationbetween MTC applications may use the services provided by a 3GPP systemand the selective services provided to the MTC server. The 3GPP systemmay provide the transmission and communication services (including a3GPP bearer service, an IMS, and an SMS) including various optimizationsfor facilitating the MTC.

It is shown in FIG. 19 that the UE used for the MTC is connected to a3GPP network (e.g., UTRAN, E-UTRAN, GERAN, I-WLAN, etc.) through anUm/Uu/LTE-Uu interface. The architecture shown FIG. 19 includes variousMTC models (e.g., a direct model, an indirect model and a hybrid model).

First, the entities shown in FIG. 19 are now described.

In FIG. 19, an application server is a server on a network on which anMTC application is executed. The aforementioned various techniques forimplementing the MTC applications may be applied to the MTC applicationserver and a detailed description thereof will be omitted. In addition,in FIG. 19, the MTC application server may access the MTC server througha reference point API, and a detailed description thereof will beomitted. Alternatively, the MTC application server may be collocatedwith the MTC server.

The MTC server (e.g., an SCS server shown in the FIG. 19) is a server ona network for managing an MTC UE, and may be connected to a 3GPP networkto communicate with a UE used for MTC and nodes of PLMN.

An MTC-InterWorking Function (MTC-IWF) may control the interworkingbetween an MTC server and an operator core network, and may play a roleof a proxy of an MTC operation. In order to support the MTC indirect orhybrid model, the MTC-IWF may relay or interpret a signaling protocol ona reference point Tsp to operate a specific function in the PLMN. TheMTC-IWF may perform a function for authenticating an MTC server beforethe MTC server establishes communication with a 3GPP network, a functionfor authenticating a control plane request from the MTC server, variousfunctions related to a trigger indication, etc.

A Short Message Service-Service Center (SMS-SC)/Internet Protocol ShortMessage GateWay (IP-SM-GW) may manage transmission/reception of a ShortMessage Service (SMS). The SMS-SC may relay a short message between aShort Message Entity (SME) (i.e., an entity for transmitting orreceiving a short message) and a UE, and may serve for astoring-and-delivering function. The IP-SM-GW may serve for a protocolinteraction between an IP-based UE and the SMS-SC.

A Charging Data Function (CDF)/Charging Gateway Function (CGF) mayperform an accounting related operation.

An HLR/HSS may perform a function for storing subscriber information(e.g., IMSI, etc.), routing information, configuration information,etc., and for providing it to the MTC-IWF.

An MSC/SGSN/MME may perform a control function such as mobilitymanagement, authentication, resource allocation, etc., for networkconnection of the UE. Regarding triggering, a function for receiving atrigger indication from the MTC-IWF and for processing it in a form of amessage provided to the MTC UE may be performed.

A Gateway GPRS Support Node (GGSN)/the Serving-Gateway (S-GW)+the PacketData Network-Gateway (P-GW) may perform a function of a gateway whichserves for connection of a core network and an external network.

Table 11 below is a summary of an important reference point in FIG. 19.

TABLE 11 Reference point Description Tsms It is the reference point usedby an entity outside the 3GPP system to communicate with UEs used forMTC through an SMS. Tsp It is the reference point used by an entityoutside the 3GPP system to communicate with the MTC-IWF related controlplane signaling. T4 A reference point used by the MTC-IWF to routedevice trigger to the SMS-SCin the HPLMN. T5a A reference point usedbetween the MTC-IWF and the serving SGSN T5b A reference point usedbetween the MTC-IWF and the serving MME T5c A reference point usedbetween the MTC-IWF and the serving MSC S6m A reference point used bythe MTC-IWF to interrogate the HSS/HLR forE. 164 MSISDN (Mobile StationInternational Subscriber Directory Number) or external identifiermapping to IMSI and gather UE reachability and configurationinformation.

In Table 11, at least one of the reference points T5a, T5b, and T5c isreferred to as T5.

Meanwhile, the user plane communication with the MTC server in case theof the indirect and hybrid model and the communication with the MTCapplication in the case of the direct and hybrid model may be performedby using the existing protocol through reference points Gi and SGi.

The 3GPP TS 23.682 document may be incorporated by reference for detailsof the description of FIG. 19.

Group Messaging/Group Based Messaging

A Group Messaging/Group based Messaging (or message delivery to a devicegroup) is proposed for an efficient device handling, and has beenprogressed as a work item, called GROUPE in current 3GPP Rel-13. In thiscase, the group messaging is assumed that the device triggeringdescribed above is simultaneously applied to a great many UEs belongedto the group, and proposed for an efficient resource management in thecase that dozens or thousands of devices such as MTC UEs aresimultaneously triggered or receive messages.

The group messaging may be used for efficiently distributing the samemessage (e.g., trigger request) to the members included in an MTC grouplocated in a specific geographical area according to the request of anSCS/Application Server (AS). Here, an example of the geographical areamay correspond to a cell sector, a cell, group of cells or a PLMN.

The group messaging may be progressed in three methods below.

1. Group messaging using a cell broadcast

2. Group messaging using an MBMS

3. Group messaging using an IP multicast

Methods 1 and 2 above correspond to methods for delivering a groupmessage such that the UEs belonged to the same group receive a cellbroadcast message (case 1) or MBMS data (case 2) in the broadcastscheme, not the unicast scheme.

Hereinafter, the group messaging using the cell broadcast will bedescribed.

The group messaging may be used for triggering a group of MTC devices ortransmitting a message when the geographical area where the devices arelocated is known and/or when a subset of the device in the MTC grouplocated in a specific geographical area is required to be triggered. Inthis case, the group messaging may be broadcasted based on the cellbroadcast service (CBS)/the public warning system (PWS) described above.

The group messaging using the CBS/PWS will be described by reference tothe drawing below.

FIG. 20 is a view exemplifying a group messaging architecture based onCBS/PWS in a wireless communication system to which the presentinvention can be applied.

Referring to FIG. 20, an SCS delivers a group messaging to a CBC throughan MTC-IWF, and broadcasts the group messaging in an accessed network bydelivering it to a serving node (i.e., BSC, RNC or MME).

In the group messaging architecture based on CBS/PWS, the MTC-IWFperforms the role of CBE with respect to the CBC. The architecturereuses the existing protocol such as CBC-BSC, Iu-BC and SBc fortransmitting the group messaging to the BSC/RNC/MME.

The group messaging is received in the MTC-IWF through the Tspinterface. The group messaging may include group identification (i.e.,an external group identifier, geographic information and group messageinformation. In addition, the group messaging may include RAT andnumber/frequency/rate for broadcasting trigger/message that areadditionally applicable.

Since the cell broadcast for the group messaging is indiscriminatelyprogressed and, in response to the cell broadcast group messaging, agreat many UEs transmit a signaling (nearly) at the same time, acongestion of signaling may be caused. Accordingly, a problem is causedto both of a mobile communication network provider and an MTCapplication owner. In order to distribute the responses of the triggeredUEs on time domain, a time window may be included in the group messagingsuch that a response is arbitrarily performed in the time window.

In the case that the MTC-IWF knows the geographical area where thedevices are located or a broadcast message is broadcasted throughout theentire geographical area, the geographical area information may not betransmitted on the Tsp.

The MTC-IWF configures a message ID IE to the group message for the MTCdevice triggering. The MTC-IWF may inquire to an HLR/HSS, and map anexternal group identification received through the Tsp interface to aninternal cell broadcast group identity.

In order to deliver the group messaging to a specific MTC group, thefollowing identification information of the MTC group (i.e., theinternal cell broadcast group identity) may be used.

-   -   Cell broadcast message ID IE (hereinafter, message ID)    -   Group identification information in a cell broadcast message        body, selectively

When a dedicated message ID is used for the group messaging, it isenough to map a group ID (i.e., external group identifier) to thededicated message ID in order to specify the MTC group that delivers thegroup messaging. However, when a plurality of MTC groups shares amessage ID, additional group identifier information may be added to thecell broadcast message body.

In addition, the MTC-IWF may add a time window to the cell broadcastmessage body for the randomization of a response signal transmission ofdevices.

The MTC-IWF transmits the group messaging to the selected CBC. TheMTC-IWF may inquire the HLR/HSS for selecting the CRC node fortransmitting a group messaging.

The CBC recognizes a group trigger/message, and allocates a message IDIE to the value allocated for the MTC device triggering. That is, thegroup trigger/message is distinguished through the PWS warning messageand the message ID.

FIG. 20 illustrates the CBS and the MTC-IWF as separate nodes, but theCBS and the MTC-IWF may be implemented as one node by being combined.

An MTC device which is configured to receive a broadcast message listensthe broadcast channel(s) for triggering message.

The MTC device reads the message ID used by an application and checkswhether the message is the cell broadcast message incoming to the MTCdevice. In addition, the MTC device may read the group identificationinformation in the cell broadcast message body additionally, and maycheck whether the message is the cell broadcast message incoming to theMTC device.

Based on the received application PDU, a UE performs a specificoperation. For example, the UE may generate application data orestablish a connection with SCS/AS, if it is required.

Group Messaging Transceiving Method

A Group Messaging/Group based Messaging (or message delivery to a devicegroup) is proposed for an efficient device handling, and has beenprogressed as a work item, called GROUPE in current 3GPP Rel-13.

The present invention relates to a Group Feature handling among thefeatures of 3GPP MTC Rel-13, and more particularly, to a method fordelivering a group messaging in the Cell Broadcast technique.

The group messaging method (refer to FIG. 21) using the Cell Broadcasttechnique is similar to the warning message delivery method such asCMAS/ETWS and the like described above. Accordingly, the paging mayindicate whether the group message is transmitted through an SIBmessage.

However, in the case of reusing the existing CMAS/ETWS indication in thepaging message, when the existing legacy UE that does not support thegroup messaging has the same paging occasion, the operation of receivingthe group messaging (e.g., SIB 10, 11 and 12) is performedunnecessarily, and accordingly, there is a problem that powerconsumption is occurred according to it.

Accordingly, the present invention proposes a method for transmittingand receiving a group messaging using a cell broadcast service (CBS)such that the UEs belonged to the UE group that requires the groupmessaging to enable an efficient operation without influencing thepaging procedure and the CBS of the existing legacy UE.

In order to deliver a group messaging only to the UE that supports thegroup messaging without influencing the existing legacy UE, thefollowing two methods may be used.

Option 1) a New Indicator for a Group Messaging

An indication element (IE) is defined as that indicates whether a groupmessaging is existed. In the case that the existing legacy UE (e.g., aUE that supports the CMAS/ETWS) does not support the group messaging,the UE may not detect it even though the indicator is activated. Inaddition, even though the UE detects it, the UE does not receive thecorresponding cell broadcast message (e.g., SIB 1, SIBs 10-12).

On the contrary, in the case that the group messaging indication of thereceived paging message is activated, the UE that support the groupmessaging receives the corresponding cell broadcast message (e.g., SIB1, SIBs 10-12). And, in the case that the message identifier of thereceived cell broadcast message is a group ID of the group to which theUE is belonged or indicates the corresponding group as a source, the UEperforms the operation (e.g., device triggering) indicated by the groupmessage contents.

Option 2) Group Paging

This is a method for identifying whether the UE belonged to thecorresponding group receives a group messaging by defining a UEidentifier for each group, that is, a group identity.

The UE identifier may designate an S-TMSI or an IMSI to the pagingrecord of a paging message. The group to which the group messaging isdelivered may be indicated by including the group identity in the pagingrecord without modifying the paging message by defining a group identityin a form such as the S-TMSI or the IMSI. In the case that the groupidentity of the UE itself belonged to the group is included in thepaging message, the group message is received by reading the cellbroadcast message (e.g., SIB 1, SIBs 10-12), and the operation indicatedby group message contents is performed.

A method for receiving a paging that indicates whether the UEs belongedto a group receives a group message will be described.

In order to deliver an indication on whether to receive a group messageusing a paging occasion (PO) for each UE belonged to a group withoutdefining the PO for each group, the following operation is required.

A UE monitors a paging by calculating a paging frame (PF) and a PO usingthe IMSI and the DRX cycle (or period) of the UE itself and theparameter for receiving the paging received from an eNB.

In the case that the eNB knows the IMSI value of the UE belonged to agroup or the MME delivers the IMSI value of the individual UE belongedto the group together with a group messaging delivery (e.g.,Write-Replace Group Message Request message) to the eNB, the eNB maycalculate the PO of all UEs belonged to the group using the IMSI value,and deliver the paging in the PO of all UEs.

However, in the case that there are many UEs belonged to the group orthe eNB does not know individual IMSI values of the UEs belonged to thegroup, the eNB is required to transmit the paging message regardingwhether to receive the group message in all POs (i.e., all availablePOs) allocated to the eNB for a predetermined time. In other words,since the eNB is unable to know which UE is belonged to thecorresponding group or which UEs of the corresponding group are includedin the coverage of the eNB itself, the eNB is hard to anticipate all POsof the UE belonged to the group. Accordingly, it is required to transmita paging in all POs (subframe which is available to perform paging thatthe eNB allows).

As such, when the paging message should be transmitted in a PO for eachUE, not defining a PO for each UE, the problem shown in Table 12 belowmay occur in the case of implementing two options above.

TABLE 12 Solution Problem 1 New In the case of using this option, thereis a possibility indicator that Paging False Alarm occurs,representatively. for group That is, since the group message indicationis notified messaging without distinguishing groups through a pagingmessage, when the UE which is not belonged to the corresponding groupreceives the paging in its own PO, the case may occur that the UE alsoread the cell broadcast message. In this case, the UE receives all groupmessaging (i.e., cell broadcast message), and the group messaging isdelivered to a high layer (e.g., an RRC layer). In the high layer of theUE, the message identifier of the cell broadcast message is read, and itis determined whether the group messaging is the group messaging for thegroup to which the UE is belonged. As such, a problem occurs that theoperation that a UE should read the group messaging occursunnecessarily, and the power consumption of an MTC UE increases. 2 GroupIn the case of using this option, there is a possibility paging that apaging message resource may be insufficient. As described above, inorder to indicate the indication on whether to receive the groupmessage, the eNB transmits the group messaging in all POs. In addition,in the case of transmitting the group messaging in several groupssimultaneously to the several groups, since a plurality of groupidentities occupies the paging record of the paging message throughseveral POs, the problem occurs that the paging message resource (i.e.,paging record space) that should be used for an incoming call of the UEis insufficient. Since the maximum paging record (maxPageRec) is definedto be 16 currently, the number of UEs that may perform pagingsimultaneously is 16. However, for example, in the case that four groupmessages are existed, since four group identities occupy the pagingrecord of the paging message transmitted in all POs for a predeterminedtime, the number of UEs that may perform paging simultaneously decreasesto 12.

Since a problem occurs when solution option 1 or 2 is used as shown inTable 12, the present invention proposes a group message transmissionand reception method in order to solve the problem.

Hereinafter, in describing the present invention, the ‘Group identity’(hereinafter, referred to as a group ID) may be the ‘internal cellbroadcast group identity’ (i.e., 16 bits) described above. That is, the‘group ID’ may be constructed by the ‘cell broadcast message ID’ solely,and also be constructed by a combination of the ‘cell broadcast messageID’ and the ‘group identification information’.

In addition, in the present invention, the ‘group identity’ may be anidentifier which is defined for each group separately from the ‘internalcell broadcast group identity’. For example, the ‘group identity’ may bean identifier which is allocated for each group in a form such as anIMSI (e.g., 64 bits) or an S-TMSI (e.g., 40 bits) which is allocated toa UE.

In addition, as the system information message that carries the ‘groupmessaging’ according to the present invention, SIBs 10 to 12 previouslydefined may be used, but the system information of a new type may alsobe used. Hereinafter, this is commonly called and expressed by ‘SIB x’.

1) First Embodiment (in the Case that Solution 1 is Used)

In the case that the indication (hereinafter, referred to as ‘GroupMessage Indication’) indicating whether a group messaging is existed (orwhether a group messaging is transmitted) is included in a pagingmessage, in order to decrease a False Alarm which causes a UE to read agroup message unnecessarily, assistance information may be included.

In the case that the Group Message Indication is activated in the pagingmessage, the assistance information may be used for identifying whetherthe group message for a group to which the UE itself is belonged istransmitted by the UE. That is, the assistance information indicates forwhich group the transmitted group message is.

The assistance information may include x bits. In the case that i^(th)bit that indicates the group to which the UE itself is belonged is setto ‘1’ among x bits of the assistance information, the UE reads thecorresponding group message, and through this process, the false alarmmay be decreased. Hereinafter, the i^(th) bit is referred to as a ‘Groupmessage discriminating number’.

A UE may acquire the Group message discriminating number based on agroup identity or acquiring it in the way of being configured by anetwork.

First, in the case that a UE acquires the Group message discriminatingnumber based on a group identity, the assistance information mayindicate a modular value for the group identity so that the UE mayidentify whether the group message for the group to which the UE itselfis belonged is transmitted. For example, in the case of using (groupidentity mod 10) (in the case of a unit of digit) or (group identity mod1024) (in the case of a unit of bit), the assistance information isconstructed as 10 bits such as {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, and thei^(th) bit that corresponds to group identity mod 10 value may be set to‘1’.

In addition, a network may configure the Group message discriminatingnumber to a UE through the attach procedure and/or the Tracking AreaUpdate procedure of the UE. Here, in the case that there are many groupsmanaged by the network, x bit number may be more increased. In addition,the Group message discriminating number may be the same for each group.For example, in the case that assistance information includes 10 bitssuch as {0, 0, 0, 0, 0, 0, 0, 0, 0, 0} as described above, the i^(th)bit that corresponds to the Group message discriminating number for thegroup to which the UE is belonged may be set to ‘1’.

FIG. 22 is a view exemplifying a group message transmission andreception method according to an embodiment of the present invention.

The assistance information may be included in a paging message togetherwith a group message indication or transmitted (e.g., broadcasted) to aUE with being included in an assistance message (e.g., SIB 1 or systeminformation message) separately from the paging message.

FIG. 22A exemplifies the case that the assistance information isdelivered with being included in a paging message, and FIG. 22Bexemplifies the case that the assistance information is broadcasted withbeing included in the system information.

Referring to FIG. 22A, an eNB transmits a group message indication and apaging message including the assistance information to a UE (step,S2201). In addition, the UE may receive the paging message in the casethat the UE reads the assistance information and the group informationto which the UE is belonged is activated. That is, in the case that abit corresponding to a group of the corresponding UE of the assistanceinformation received from the eNB is activated (i.e., in the case thatthe assistance information indicates that the paging message for thegroup to which the UE is belonged is going to be transmitted), the UEreads the paging message, and in the case that the group indication ofthe paging message is activated, the UE receives the group message. Inthis case, the assistance information is used for indicating whether thepaging message is transmitted for each UE group. As such, in the casethat the assistance information indicates whether the paging message istransmitted for each UE group, before step, S2201, a step for the UE toreceive the assistance information from the eNB may be added, and thepaging message may not include the assistance information in step,S2201.

In this case, when the eNB receives a message (e.g., Write-Replace GroupMessage Request message) that requests a group message transmissionincluding a group identity and/or a Group message discriminating numberfrom a network (e.g., MME), the eNB may identify the UEs belonged to thegroup that corresponds to the group identity. And, the eNB may transmitthe paging message that includes the group message indication and theassistance information for distinguishing the corresponding group to theUE on the paging occasion of the UEs belonged to the corresponding groupor on all available paging occasions for a predetermined period. In thiscase, the assistance information (in the case of not being included inthe paging message) may be transmitted through the system information ora common control channel.

In addition, the eNB transmits the group message to the UEs belonged tothe corresponding group (step, S2202).

For example, in the case that a modular value (e.g., group identity mod10) for the group identity to which the UE is belonged is ‘4’, or aGroup message discriminating number configured to the group to which theUE is belonged is ‘4’, a group message transmission to the UE isactivated (group message indication value is ‘true’). And, in the casethat the UE receives a paging message that includes {0, 0, 0, 0, 0, 1,0, 0, 0, 0} as the assistance information, the UE recognizes that itsown group message is transmitted and receives a cell broadcast message(i.e., group message).

On the contrary, the UEs of which modular value for the group identityto which the UE itself is belonged is not ‘4’ or the UEs of which Groupmessage discriminating number configured to the group to which the UE isbelonged is not ‘4’ do not receive the cell broadcast message (i.e.,group message).

That is, in the case that the group message indication value in thepaging message is ‘true’ and the assistance information indicates thegroup to which the UE is belonged, the UE receives the group message. Inother words, based on the group message indication and the assistanceinformation, it is determined whether the UE receives the group message.

As described above, the assistance information may not be included inthe paging message but may be transmitted before the paging message.Even in this case, the assistance information may be constructed in thesame way above. For example, the assistance information includes 10 bitsand each bit position indicates the modular value of the UE IMSI. Whenthe UE receives the assistance information before its own PO and the bitposition mapped to its own IMSI mod 10 in the assistance information isactivated (i.e., ‘true’ or ‘1’), the UE may wake up from its own PO andreceive the paging message. On the contrary, when the bit positionmapped to its own IMSI mod 10 in the assistance information is notactivated, the UE does not receive the paging message.

In the case that the eNB transmits a cell broadcast message (i.e., groupmessage) to the UE through its own system information message, the eNBmay transmit the scheduling information list (schedulingInfoList) forthe system information message (e.g., SIB x) that carries a groupmessage to the UE through an SIB 1 message. And, the eNB may transmitthe group message to the UE through the system information message(e.g., SIB x).

Referring to FIG. 22B, the eNB transmits a paging message that includesa group message indication to the UE (step, S2211).

And, the eNB transmits the assistance message that includes theassistance information to the UE (step, S2212).

In this case, when the eNB receives a message (e.g., Write-Replace GroupMessage Request message) that request a group message transmission thatincludes a group identity and/or a Group message discriminating numberfrom a network (e.g., MME), the eNB may identify the UEs belonged to thegroup that corresponds to the group identity. And, the eNB may transmitthe paging message that includes the group message indication on thepaging occasion of the UEs belonged to the corresponding group or on allavailable paging occasion for a predetermined period, and transmit theassistance message that includes the assistance information fordistinguishing the corresponding group to the UE.

Here, as an example of the assistance message, the SIB 1 message orsystem information may be used, and in this case, the SIB 1 message mayinclude the assistance information together with the schedulinginformation list (schedulingInfoList) for scheduling the group message.

And, the eNB transmits the group message to the UE belonged to thecorresponding group (step, S2213).

For example, in the case that a modular value for the group identity towhich the UE is belonged is ‘4’, or a Group message discriminatingnumber configured to the group to which the UE is belonged is ‘4’, agroup message transmission to the UE is activated (group messageindication value of the paging message is ‘true’). And, in the case thatthe UE receives the assistance message (e.g., SIB 1) that includes {0,0, 0, 0, 0, 1, 0, 0, 0, 0} as the assistance information, the UErecognizes that it is the paging information for its own group andreceives a cell broadcast message (i.e., group message).

On the contrary, the UEs of which modular value for the group identityto which the UE is belonged is not ‘4’ or the UEs of which Group messagediscriminating number configured to the group to which the UE isbelonged is not ‘4’ do not receive the cell broadcast message (i.e.,group message).

That is, in the case that the group message indication value in thepaging message is ‘true’ and the assistance information in theassistance message indicates the group to which the UE is belonged, theUE receives the group message. In other words, based on the groupmessage indication and the assistance information, it is determinedwhether the UE receives the group message.

2) Second Embodiment (in the Case that Solution 2 is Used)

In the case that a group paging is used, a Group specific pagingoccasion may be newly defined. This will be described by reference todrawing below.

FIG. 23 is a view for describing a group paging occasion according to anembodiment of the present invention.

In FIG. 23, it is assumed that a group includes a first UE (UE 1) and asecond UE (UE 2). In addition, it is assumed that the same DRX cycle andthe same paging frame (PF) are configured to all of the UE (UE 1 and UE2) belonged to a specific group regardless of individual paging occasionand group paging occasion.

Referring to FIG. 23, in the case of a Group specific paging occasion isdefined, an MTC UE, that is, the UE belonged to a group has two types ofpaging occasions. In FIG. 23, a group paging occasion (2301) and its ownspecific paging occasion 2302 are configured to the first UE, and thegroup paging occasion 2301 and its own specific paging occasion 2303 areconfigured to the second UE.

The UE belonged to a specific group may calculate the Group pagingoccasion using a group identity in addition to the paging occasioncalculated by the IMSI value of the individual UE.

As described above, the paging occasion is calculated by a UE-ID, a DRXcycle and the parameter broadcasted in a cell. That is, in order for theUE to receive an individual paging in Equation 2, the UE-ID iscalculated in IMSI mod 1024, and in order for the UE to receive a grouppaging, the UE-ID is calculated in Group ID mod 1024.

As such the UE that receives a group message calculates two pagingoccasions. The UE wakes up two times, receives the individual paging forone time and receives the group paging for the remaining time.

As such, when the group paging occasion is defined, since the groupidentity for delivering the group messaging is included in the pagingmessage only on the group paging occasion, as described above, theproblem may be prevented that the group identity is included in allpaging messages during a predetermined time, and influences the pagingcapability of the existing UE.

Meanwhile, in FIG. 23, the case is exemplified that the DRX cycle forthe individual paging and the DRX cycle for the group paging are thesame for the UEs (i.e., the first UE and the second UE) belonged to thecorresponding group, but the present invention is not limited thereto.That is, the DRX cycle for the UE individual paging and the DRX cyclefor the group paging may be separately configured. In this case, the DRXcycle for the individual paging may be configured for each UE in agroup, and in addition, the DRX cycle for the group paging may beconfigured to all of the UE in the group commonly.

In addition, the case is exemplified that the paging frame for theindividual paging and the paging frame for the group paging are the samefor the UEs (i.e., the first UE and the second UE) belonged to thecorresponding group, but the present invention is not limited thereto.That is, the paging frame for the UE individual paging and the pagingframe for the group paging may be separately determined. For example, inorder for the UE to receive the individual paging in Equation 1 above,the UE-ID may be calculated in IMSI mod 1024, and in order for the UE toreceive the group paging, the UE-ID may be calculated in Group ID mod1024.

FIG. 24 is a view exemplifying a group message transmission andreception method according to an embodiment of the present invention.

Referring to FIG. 24, an eNB transmits (e.g., broadcasts) a pagingmessage that includes a group identity to a UE just on a group pagingoccasion (step, S2401).

In this case, when the eNB receives a message (e.g., Write-Replace GroupMessage Request message) that requests a group message transmission thatincludes the group identity from a network (e.g., MME), the eNB mayidentify the group corresponding to the group identity. And, the eNB maytransmit a paging message on the group paging occasion which isdetermined based on the corresponding group identity to the UE.

And, the eNB transmits the group message to the UE belonged to thecorresponding group (step, S2402).

The UE wakes up on the group paging occasion determined based on thegroup identity which is allocated to the group to which the UE isbelonged, and receives the paging message transmitted from the eNB. And,in the case that the group identity of the group to which the UE isbelonged is included in the paging message, the UE identifies that itsown group message is transmitted, and receives a cell broadcast message(i.e., group message).

In this case, in the case that the eNB transmits the cell broadcastmessage (i.e., group message) to the UE through a system informationmessage, the eNB may transmit a scheduling information list(schedulingInfoList) for the system information message (e.g., SIB x)that carries the group message to the UE through the SIB 1 message. And,the eNB may transmit the group message through the system informationmessage (e.g., SIB x).

Meanwhile, since the UE that supports the group paging should performboth of the UE individual paging reception and the group pagingreception, the UE should wake up two times during the DRX period.

Accordingly, a network may configure an MTC UE that mainly uses a mobileoriginate call and does not requires a mobile terminated call or the UEsthat is available to be processed by the group messaging only to receivethe group paging only. For example, during an attach procedure and/or atracking area update procedure, the network may command thecorresponding UE to receive the paging for the group message only by theGroup message capability and subscriber information and theconfiguration information of an MTC user.

In this case, the corresponding UE checks whether the group message istransmitted by identifying the paging message only on the pagingoccasion calculated by the group identity, not on the paging occasioncalculated by its own IMSI value. And, in the case of receiving thecorresponding group message, the UE performs an operation according tothe contents of the received group message.

In addition, a network may selectively use two embodiments aboveaccording to the number of groups. That is, in the case that there aremany groups and the paging capacity is insufficient, the network mayselect the method according to the second embodiment that uses the Groupspecific paging occasion. However, in the case that there is a fewgroups, the network may use both of the method according to the firstembodiment that uses the Group message indication and the methodaccording to the second embodiment that uses the Group specific pagingoccasion.

Overview of Devices to which the Present Invention can be Applied

FIG. 25 illustrates a block diagram of a communication device accordingto one embodiment of the present invention.

With reference to FIG. 25, a wireless communication system comprises anetwork node 2510 and a plurality of UEs 2520.

A network node 2510 comprises a processor 2511, memory 2512, andcommunication module 2513. The processor 2511 implements proposedfunctions, processes and/or methods proposed through FIG. 1 to FIG. 24.The processor 2511 can implement layers of wired/wireless interfaceprotocol. The memory 2512, being connected to the processor 2511, storesvarious types of information for driving the processor 2511. Thecommunication module 2513, being connected to the processor 2511,transmits and/or receives wired/wireless signals. Examples of thenetwork node 2510 include an eNB, MME, HSS, AS, SCS, and so on. Inparticular, in case the network node 2510 is an eNB, the communicationmodule 2513 can include an Radio Frequency (RF) unit fortransmitting/receiving a radio signal.

The UE 2520 comprises a processor 2521, memory 2522, and communicationmodule (or RF unit) 2523. The processor 2521 implements proposedfunctions, processes and/or methods proposed through FIG. 1 to FIG. 24.The processor 2521 can implement layers of wired/wireless interfaceprotocol. The memory 2522, being connected to the processor 2521, storesvarious types of information for driving the processor 2521. Thecommunication module 2523, being connected to the processor 2521,transmits and/or receives wired/wireless signals.

The memory 2512, 2522 can be installed inside or outside the processor2511, 2521 and can be connected to the processor 2511, 2521 throughvarious well-known means. Also, the network node 2510 (in the case of aneNB) and/or the UE 2520 can have a single antenna or multiple antennas.

The embodiments described above are a combination of constitutingelements and features of the present invention in particular forms.Unless otherwise specified, each constituting element or feature shouldbe regarded to be selective. Each constituting element or feature can beembodied solely without being combined with other constituting elementor feature. It is also possible to construct embodiments of the presentinvention by combining part of constituting elements and/or features.The order of operations illustrated in the embodiments of the presentinvention can be changed. Part of a structure or feature of anembodiment can be included by another embodiment or replaced with thecorresponding structure or feature of another embodiment. It should beclear that embodiments can also be constructed by combining those claimsrevealing no explicit reference relationship with one another, or thecombination can be included as a new claim in a revised application ofthe present invention afterwards.

Embodiments according to the present invention can be realized byvarious means, for example, hardware, firmware, software, or acombination thereof. In the case of hardware implementation, theembodiments of the present invention can be implemented by one or moreof ASICs (Application Specific Integrated Circuits), DSPs (DigitalSignal Processors), DSPDs (Digital Signal Processing Devices), PLDs(Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays),processors, controllers, microcontrollers, microprocessors, and thelike.

In the case of firmware or software implementation, methods according tothe embodiment of the present invention can be implemented in the formof a module, procedure, or function performing operations describedabove. Software codes can be stored in a memory unit and executed by aprocessor. The memory unit, being located inside or outside theprocessor, can communicate data with the processor through various meansknown in the fields of the art.

It should be clearly understood by those skilled in the art that thepresent invention can be realized in a different, particular form aslong as the present invention retains the essential features of thepresent invention. Therefore, the detailed description above should notbe interpreted limitedly from all aspects of the invention but should beregarded as an illustration. The technical scope of the invention shouldbe determined through a reasonable interpretation of the appendedclaims; all the possible modifications of the present invention withinan equivalent scope of the present invention should be understood tobelong to the technical scope of the present invention.

INDUSTRIAL APPLICABILITY

The method for transmitting and receiving a group messaging in awireless communication system of the present invention has beendescribed mainly with the example applied to 3GPP LTE/LTE-A system, butmay also be applied to various wireless communication systems except the3GPP LTE/LTE-A system.

The invention claimed is:
 1. A method for receiving a group messageperformed by a user equipment (UE) in a wireless communication system,the method comprising: calculating a group specific paging occasion forthe UE using a group identity, wherein the UE belongs to a group, hasits own specific paging occasion and the calculated group specificpaging occasion; receiving, from a network node, a paging message on thegroup specific paging occasion to receive a group message; receiving,from the network node, a system information message when the pagingmessage includes a group message indication, wherein the systeminformation message includes assistance information for identifying agroup to which the group message is transmitted and schedulinginformation for scheduling the group message; and receiving, from thenetwork node, the group message based on the scheduling information,when the group message for the group to which the UE belongs istransmitted based on the assistance information.
 2. The method of claim1, wherein the assistance information indicates the group identityallocated to each UE group or a modular value for an InternationalMobile Subscriber Identity (IMSI) for the UE.
 3. The method of claim 1,wherein the assistance information indicates a group messagediscriminating number which is predetermined for each UE group.
 4. Themethod of claim 3, wherein the group message discriminating number isconfigured through an attach procedure or a tracking area updateprocedure.
 5. The method of claim 1, wherein the group message istransmitted through a system information message.
 6. A method fortransmitting a group message performed by a network node in a wirelesscommunication system, the method comprising: receiving, from a networknode, a message that requests a group message transmission;transmitting, to a user equipment (UE), a paging message on a groupspecific paging occasion of the UE, wherein the paging message includesa group message indication; transmitting, to the UE, a systeminformation message, wherein the system information message includesassistance information for identifying a group to which a group messageis transmitted and scheduling information for scheduling the groupmessage; and transmitting, to the UE, the group message based on thescheduling information, when the group message for the group to whichthe UE belongs is transmitted based on the assistance information.